i opened up an 80kb xls file (it had one sheet with about 600 rows and 3 columns of voltages values from a picoscope, and then a graph on those values on the same sheet)
That's interesting; I was having trouble with an electronics-related graph too. In my case it was about 8000 rows and 28 columns of data with the related graph. (simulating a cycloconvertor on a three-phase motor)
Maybe it's largish graphs which cause the trouble; I have a similar file without a graph and it comes right up.
The main thing that matters to most people in an MS Office replacement is how well it reads and writes MS Office files. And that's, unfortunately, a moving target.
Agreed on both points. My experience with 641C (win and linux) is that it reads and writes Office97/2000 files with ease. Really large excel files it barfs on, but your normal.doc with graphics, "normal size" xls files, etc. all work great. I was really surpised at how well it writes the files, too.
And I don't understand the concept of PGP Sigs either.. How does that prove anything? What's to prevent me from smacking a PGP Sig on my email? Does anybody verify those?
I use KMail; it has very nice GnuPG integration, the only missing feature is for *it* to go through and encrypt my attachments instead of making me do it. At any rate, any email with a PGP sig is automatically checked and since I have the colour bar enabled signed messages with keys I trust (and that pass) are in a green border. Good sigs with keys I don't know/trust are in a yellow border and bad signs are in a red border. Very eye-catching and very nice.
I generally sign messages (not encrypt) if I want to give the person on the other end a way of verifiying that what I sent didn't get altered. I encrypt when I don't want anyone else reading it. It's perhaps a subtle difference, but I use it quite often.
It actually takes longer than 20 minutes if you think about it.
I did think about it. Bad hardware can happen on brand-names, too, and you're still out the time to get it replaced. Week-long delays happen with brand-names, too. I fail to see how this is a non-brand-name problem.
I stand behind my time of 20 minutes; if you've got all the hardware and none of it's bad (not that hard to do, really, but sometimes you get screwed), it takes no longer than twenty minutes to get the hardware into the case and get the screws done up.
disc imaging tools such as ghost don't have anything to do building a computer from scratch.
I think it is you who is missing the point.
How long does it take you to assemble a computer? About 20 minutes, tops? Thought so. Now how long does it take you to take that fresh Win2k install and run over to windowsupdate.com a half dozen times, rebooting after every one? Now install Office, Citrix, the in-house apps, set up the email software, grab the templates, etc.? Thought so. The time wasted is in software installation, not physical computer assembly. Buying a computer from Dell or building one from off the shelf parts is inconsequential.
And you are forgetting the tech support center's secret weapon: automation.
The crew at the company I work for can do a Win2k install by installing a CD, attaching a network cable and powering up. About 90 minutes later is a full standard 2k install, including all the apps and service patches and whatnot we've standardized on. If we had exact hardware across the board we could Ghost it even faster.
That $300 labour charge is only incurred when you have to babysit the install. Hell even my Slackware-based firewall installs go in in about 15 minutes now because I use custom tagfiles and a few of my home-rolled packages.
I find it interesting that out of several paragraphs of diatribe, a single phrase, with the magic word "union" in it, generated the string of responses, while the rest of the message seems to have slipped under the radar.
I was wondering if someone was going to point that out. I was reading the threads and your comment stuck out, and yes it was partly because of the word 'union.' It seemed to try and offer that the only way to avoid a real-life Alien environment is through your union badge. That and the insinuation that people (specifically Americans) who oppose unions are somehow pampered.
I'll be the first to admit that the word 'union' has some very negative connotations. Hell with the Canadian Auto Workers and OPSEU (Ontario Public Servants), the Teacher's Union and so on it's hard not to equate the word 'union' with 'old boy's club' -- everytime I see or read about a union it's in a negative connotation.
Now the idea behind unionization is a good thing; don't get me wrong. However a true union is about as hard to achieve and maintain as a true communist society. People are lazy and no matter how many rules you try to circumvent this, you'll end up with a system designed to pamper people at the top.
The fundamental irony of the situation is, most of the people here who are "free agents" working for the Man, can't see that in the Cave, their shadows are just as chained as the poor savages' are.
I can faintly see your point here but I'm afraid most of it is lost on me due to the metaphor; can you make it a little clearer for me? I have the sneaking suspicion that I do agree with you.:-)
Pampered Americans--those who cheer scabs over unionization--are reaping the whirlwind they've sown.
That's funny, because I see it the exact opposite.
What union values skill over seniority? What union congradulates effort over doing the minimum? I can't think of a single one. It's the unions which promote pampered "Americans" -- I would call them pampered employees, not the ones who refuse to work for such an assinine old-boys club.
The higher voltages is how it gets through all of the distance.
Incorrect; the voltage is only used to power repeaters and the CPE; the actual data transmission is done with low-voltage signals. If you increase the voltage swing or push more current, you end up increasing crosstalk and that brings you bigger troubles, which is why they use repeaters in the first place. It's the use of repeaters which give you the incredible distances that T1/E1 circuits can span, and the repeaters rely on the static -130VDC on the line.
Fibre-optic transocean lines do the same thing. You don't want to cut through a long-haul fibre line because they have thousands of volts across a couple of their internal metal layers to provide power for the ocean-floor optical repeaters.
While most repeaters take the -130V provided across the T/R and generate their own internal power supplies from it, some types of repeaters will take a -48VDC power source and regenerate the -130VDC for the next 50km or so, just as the CO-end equipment does. The -130VDC is current-limited (you're running on thin wire remember) and as such it just doesn't go all that terribly far. Powered circuits are only there to make life easy in remote locations (you don't need power handy), not to make the signal stronger. That's what regeneration and repeaters are all about.
That's odd. Perhaps HDSL runs differently, but the references say that a T1 should run at 2.7-3.3v, from AT&T publication 43801.
That sounds like a DSX1 spec; is that publication online? A quick google check find shitloads of references to it.:-(
You have a reply from djweis which says it's the voltage that cuts through the distance; this is untrue. The voltage is only used to power repeaters and the CPE; the actual data transmission is done with low-voltage signals. If you increase the voltage swing or push more current, you end up increasing crosstalk and that brings you bigger troubles, which is why they use repeaters in the first place.
Consider SDSL; not powered, and the range is similar to a standard HDSL2 circuit -- with HDSL(2), you can add repeaters since the line is powered; I can't do that with my SDSL circuits. It's a simple cost/distance tradeoff.
Consider that most COs run on -48v. To get 130v, they need to multiply voltage 2.7083 times. To get -3v(avg of 2.6-3.3), divide -48v by 16.
The electronic specs are not derived by easy to multiply/divide ratios like most things in the computer industry. The -130VDC is generated by the CO equipment using a simple boost regulator, which in turn runs off of the -48VDC float-charged lead-acid batteries you mention. I can create a 3.3V regulator or a 3.45V regulator with any input voltage; the real world is analog, which is why I love analog electronics design.:-)
I'm not really sure what you mean by this. Clock is regenerated by the remote end points of a DS3. There is no clock information carried through the circuit at the DS1 level.
You're right, they're re-clocked. I had to review the DS3 aggregation notes from Cisco. It's DS3s which have the slop bits, I don't think DS2s do this (they re-time the DS1s) -- I've never really worked with an actual DS2 so I don't know for absolute sure.
No, a DS3 is a completely different beast, with its own framing,coding, and timing rules.
That's what I was getting at; the DS3s (well the ones which are used to aggregate anyway) have all kinds of funky things going on inside but none of it is really all that interesting (at least not to me).
Um, no. Voltage supplied at the CO is completely determined by how many repeaters are on the line. You should end up with something like 12 volts at the CPE. -130VDc at the CPE would burn up just about anything you put on it, and would definately screw up a sinsitive test set.
This is incorrect. I just measured across the HDSL circuit here. -126VDC, no repeaters that I know of (3km circuit). Circuits in parallel (essentially what we have here) have equal voltage across them. Having to engineer the voltage for every circuit would be a royal pain in the ass. Actually for fun, take your HDSL CPE end, and take a good autotransformer and diode bridge. Connect the diode bridge + and - to T and R (polarity doesn't matter) -- now slowly bring up the autotransformer. The CPE end won't even light up until around 85V or so.
The guy at the telco almost certainly does NOT know how this stuff _really_ works. I've had to explain alarm codes to more than one "senior engineer". DON'T let him get off the phone. If he doesn't have a test set, hold on the phone until he does. Escalation is your friend.
haha, yes you are very correct here. Find someone and find some way to get their pager, cell and office numbers. And hold on to them because a good tech is very hard to find.
Ancient tech, dating back to the '60s D1 circuits. I believe there was an F1 as well which used frequency-division multiplexing (i.e. what cable does) instead of time-division multiplexing. That's a real pain in the ass because the filters get very complex, and time-division multiplexing is dead-simple these days.
Your line between your house and the CO is very simple. It's a pair of twisted copper wires with some control voltage singalling (-48VDC on-hook, ~-8VDC on-hook, ~90VAC ring). When it hits the CO though it gets filtered (400-4000Hz) and digitized (PCM I believe) at 8 bits/8kHz and stuffed into a channel on a T1 if it's heading out to another CO.
These days you usually have equipment between the FXO and the switch which strips off the high frequency data and gives that to a DSLAM/RedBack/etc. but this is about voice.
A single voice communication channel is referred to as a DS0 and codes at 64kbps (8 bits * 8000 samples/sec). There are 24 DS0s in a DS1 (the data specification of a T1 is a DS1). Every DS1 frame has a framing bit. So 24 * 8 + 1 is 193 bits. Those 193 bits are sent 8000 times a second to give you your raw DS1 speed of 1.544Mbps. The frame is reserved though so you really get a useful bandwidth of 1.536Mbps.
In the olden days T1 circuitry required the frame bit to always be a '1' to maintain sync. These days the endpoint circuitry has no trouble keeping sync and the frame bit is used for "out of band" signalling. You figure 1 free bit 8000 times a second, that's a nice 8kbps of "free" information. This OOB channel is used to talk to the remote end to do things like loopback, QoS checks, etc. since it does not interfere with the data travelling in the 24 individual DS0 (data) channels. Pretty neat trick.
Now the actual electrical signals travelling those distances aren't 0v and 1v; it'd be impossible to get any data across. One of the first methods of electrically transmitting the data was AMI - Alternate Mark Inversion. A 0 (space) would be sent as no pulse, and a 1 (mark) would be sent as a pulse in the opposite direction of the last pulse. This kept the net DC voltage on the line at 0V (important for clock recovery), and simple flip-flip circuitry could be implemented to detect a bipolar violation (two consecutive pulses in the same direction).
Back when T1s were used ONLY for voice, nobody had to worry about long strings of 0s since it was statistically impossible to keep a PCM-coded voice channel at absolute zero, and the forced-1 state of the frame bit kept the framer in sync. Nowdays though T1s can carry data and it is easily possible to have long strings of 1s or 0s. Something had to be done.
With a long string of 1s you get a long string of "+1 -1 +1 -1..." (alternate pulse for each mark, remember) -- no problem. However a zero was coded as the absence of a pulse which meant that a long string of zeros would tend to have the clock sync drift since there were no pulses to sync to. B8ZS was born.
B8ZS (Binary 8 Zero Substitution) used a trick already used in low speed, short-haul communications such as RS232: escapes. A run of 8 zeros is sent as a specific error: "+1 + 1 0 0 -1 -1 0 0." The circuitry on the other side would see two BPVs (Bipolar Violations) in that specific pattern and instead of flagging an error, it would spit out 00000000. DS3s do the same trick with B3ZS. (aside: DS3 = 7 DS2 = 4 DS1, or 672 phone lines on a pair of coax cables)
Let's skip back to voice for a second. Remember how you have 24 voice channels being sent in a T1? Well as described, there is no way to tell if the line is on-hook, off-hook, ringing or busy. The solution was to steal a bit from each channel every so often and use that bit to represent line state. Since you're actually pissing around with the data, it's called in-band signalling, and specifically here, robbed-bit signalling.
What the telcos did was design a new framing system that used 12 DS1 frames as it's frame. Take 12 of those 193 bit frames and ear-mark #1 and #6. Now when Frame #1 comes along you will ignore whatever the LSB was for each DS0 and instead inject an "A" bit. And when #6 comes along you will do the same but inject a "B" bit. This big frame (12 DS1 frames) became known as the Super Frame.
What a normal DS1 frame looks like: (F = frame, A = A bit, B = B bit, 0-7 = PCM-coded voice traffic)
DS0#0 DS0#1 DS0#2... DS0#23 F 01234567 01234567 01234567... 01234567 F
And for DS1 Frame #1:
DS0#0 DS0#1 DS0#2... DS0#23 F A1234567 A1234567 A1234567... A1234567 F
DS1 Frame #6:
DS0#0 DS0#1 DS0#2... DS0#23 F B1234567 B1234567 B1234567... B1234567 F
See how each channel gets an A and B bit?
What they did with the A and B bits was inject line state. 2 bits = 4 states. Now the CO can give you a busy signal or a ringback tone.
The telcos didn't stop there; they went on to give us the Extended Super Frame -- 24 DS1 Frames where every 6th frame has the LSB of the DS0s robbed to give you A, B, C and D bits. Most implementations just have the C and D bits mirror the A and B bits for now, but now you have 16 states to describe each channel in a DS1. This type of in-band signalling is known as robbed-bit signalling and is the reason you're at 56kbps for dialup. The modems actually do try and sync up to the DS1 framing and detect the robbed bit signalling when they trainup but really it's not going to get you much more speed to try and code at 64kbps 5/6th of the time and 56kbps 1/6th of the time. This robbed-bit signalling is only used on POTS; in data it's unnecessary because with ISDN your control info is in a separate D channel and for channelized-T1 it's not necessary.
I always feel like I'm talking about wrestling when I talk about SupaFrames and Extended SupaFrames:-)
Voice is always channelized; there are discrete conversations that have nothing to do with each other jammed together and transmitted as a group. Data T1s can come in channelized and unchannelized varieties. Basically it is used to group voice and data on a single T1, or, like voice, to group unrelated data communications together in an aggregate link for more efficient transmission.
Say you have a T1 between two offices and you want a 128bps link too. Well each DS0 is 64k, right? So they can take two DS0s and "split them off" for data, passing the other 22 for voice calls between the PBXes or KSUs or whatnot. Or if you want two 256k data links to two different areas; it can be done with one physical T1 to the CO, and then two from there to the locations. That's all that channelizing is about; aggregating datastreams into one connection.
Oh yes, ISDN. You'll recall that ISDN BRI is 64kbps. Guess what? An ISDN B channel is just one DS0, with the signalling occupying part of a 4kbps D channel. You can get fancy with something called Non-Facillity Associated Signalling which lets you cluster up to 8 DS1s' worth of D channels into a single B channel; That's right, with the right equipment termination you can combine up to 191 B channel control signalling into a single 64kbps D channel. (I don't think it's called a D channel anymore but I'm not sure on this.) -- dialup ISPs use it to try and regain lines when using PRIs, since a normal ISDN PRI is 23 B channels and a D channel (i.e. you lose a DS0 to signalling).
I briefly mentioned DS2s and DS3s. A DS2 is just an aggregation of 4 DS1s. The data bandwidth is not exactly 4*1.536mbps (frame is stripped out) because there are some slop bits set aside because the individual T1s coming in will not be synchronized and the slop bits take care fo that. It's the same with DS3s, which are made up of 7 DS2s. Not really exciting, because all the work was done at the DS0/DS1 level.:-)
Electrically, a DS1 is usually sent as an HDSL circuit these days; there really aren't any T1s to speak of anymore. DS = Data Specification (IIRC), where a T1 is just a DS1 with the electrical spec glued to it. Normally you have -130VDC on the line (supplied by the CO end) and the remote end (and any repeaters) get their power from the line. Pretty nifty. You can go up to 650 feet without powering the circuit if I remember correctly; unpowered DS1s are usually refered to as DSX1s.
Troubleshooting-wise you don't run into much these days. The CPE and CO ends almost always have serial ports and you snap on a laptop and ask it what's wrong or set up loopbacks and so on. The old days of having one end in a hot location and the other in shade and having that cause temp-related sync issues are long past.
So, there's almost everything you need to know about T1s. No need to buy a book that goes into the same detail.:-)
Lack of MSN Messenger is solved by grabbing Psi, a kick-ass jabber client. (Best I've used on Win32 or Linux).
I've never had trouble with my X Server bombing, but then again I've compiled my own XFree86 4.1.0 from source (not sure why I did it originally). Your CD Creator is a problematic one though, but it is coming.
As far as file sharing goes, I just use LimeWire's Java client. It's actually not too bad with the IBM Java compiler. You're right on when it comes to media though, although this too is coming.
KDE3 from CVS simply rocks, and if you don't want to compile it all yourself just grab the latest 3.0 beta; it's not far off from the CVS right now. I've been running Slack on my notebook for almost two years now, trying both Win4Lin and VMWare for the Windows things I need. If Win4Lin's support didn't suck so hard I'd have stuck with them but now that I only use Windows for the P&E Micro flash tools and some in-house Win32-only software, I hardly need to look at the Start button anymore. WindowMaker with KDE is a very nice combination; there are only two things weird. Klipper must be running or you get some very strange clipboard operation, and Java windows do not sit in the Konqueror "page" -- they are created as new toplevel windows.
All in all I tend to agree with you that Linux is almost ready. Almost. KDE has come a LONG way; it *is* ready for corporate offices but not for home users; I can deploy OpenOffice and KDE on anyone's workstation here and almost not have them notice.:-)
If I'm in public somewhere, I'm not leaving my laptop unattended.
actually what I do whenever I get a new laptop (this is my third, none stolen, just upgrades) is to remove the hard drive retaining screw; the drive is usually in some kind of carrier that is connected to the rest of the laptop by a single screw. Whenever I go somewhere and I don't want to lug the laptop with me, I pop out the drive. Laptops are easily replaced and are insurable. Backups I have but it's still a pain in the ass and if I'm out for a few days the work isn't backed up. The data loss is far worse than the actual theft.
If there's one thing I hate, it's Faq-o-Matic. I have never been able to get decent information out of such a mega-hyperlinked irritatingly-coloured monstrosity as Faq-o-Matic. That includes OpenLDAP's FAQ-o-Matic, Amanda's FAQ-o-Matic, Lynx's FAQ-o-Matic and FAQ-o-Matic's own FAQ-o-matic. Clicking a hundred links to get to a single paragraph that almost, but not entirely completely fails to answer the question is more annoying than not having an entry at all. And why does every FAQ-o-Matic seem to be hell-bent on experimenting in shades of puke for the colour scheme? Lynx's FOM doesn't follow this trend but damn near every single FOM on the planet is butt-ugly in addition to being terrible to navigate.
Provide FAQs in plain, easy to read HTML or text. Screw FAQ-o-Matic.
What I'd like to see is something along the lines of some kind of LRU which gently starts swapping data back into memory from swap when memory becomes free. There's nothing like having VMWare sitting in swap since you stopped using it an hour ago to do some other work and then jumping back and having to wait the 5-10 seconds of heavy disk activity to resume work there.
As for those saying "don't use swap at all" -- that's crazy talk. I'd rather have an app or two go to swap instead of being outright killed by the VMM when it needs an extra meg or so. If I'm not mistaken Linux tends to pick the big memory eaters to dump to swap over the little guys so if you start a compile... there goes VMWare... or your IM client... or Konqueror... lots of fun.:-)
The Windows XP 'powertool' has a very useful feature that allows you to enter a shortcut for a search engine. So if I type 'g privacy' it sends off a search to Google for 'privacy'.
Not a personal attack, but is this supposed to be an innovation of Windows? Both Konqueror and Opera have had this for quite some time now.
f you replace the openssl while SSH is running it will detect the version change and kill all running sshd sessions. Then you'll have a half installed openssl and not be able to start sshd.
Not entirely true; I had one server do this to me, but the six others that I upgraded work fine... update openssl, update openssh, kill running sshd parent, run new one, verify, exit. no problems.
If anyone can exlain why this one system may have done that, I'd appreciate it. It did this tlast time around too.:-(
you mean the one that requires you to set up 3 accounts for the client, 3 accounts for the server, and comes with its own inetd replacement?
You forgot the part about the code being totally undocumented (including no descriptive variable names whatsoever) and that it will only securely talk to djbssh clients since ssh is a useless tool of a protocol that should have never been passed as in RFC.:-)
qmail is an awesome program. Too bad it's almost impossible to understand the code.:-(
That's because until version 3, Qt had a broken implementation of the X clipboard. With the advent of Qt 3 and KDE 3 it is expected that we will finally have a unified clipboard across X applications. That will happen in, say, a month.
I forgot to mention: I am running KDE3 CVS. Trust me, it's a big improvement, but still two clipboards.:-)
I vaguely remember reading that it would come with two options: standard linux cut&paste or windows-like cut and paste. How can you complain against options like that?
Easy; unless you're in a totally KDE environment, you get a mix of the two. I live with it every day on this notebook. KDE for almost everything, OpenOffice 6 for office, and WindowMaker and aterm pulling up the rear (well Citrix is in there too). I have *two* clipboards and *both* cut and paste methods... I've gotten used to it but it was frustrating for a while.:-)
My advice to all of you remaining Ebayers... please, use Escrow. I was one of a lucky few.
Lucky few my ass. It's the unlucky few who make the most noise. How many successful auctions does ebay have? Uh huh, and now in how many of those is the seller/buyer scammed? Ok, that's what I thought.
I've bought well over USD$50k of product via ebay over the past 5 years or so. Cisco access servers, mostly, but there has also been notebooks, routers, switches, electronic design gear (meters, oscilloscopes, logic analyzers etc.), manuals, software and my wife's SLR camera. No shit. The only time I used escrow was for an order of 6 Palm Pilot Vxes with keyboards and travel cases, but that was because that particular auction felt "funny".
I've only been ripped off once; I won an auction for the game Drowned God. It's a three-CD game in which the CDs come in a boxboard holder; I had lost my set and found them years later in the garage in a pool of water. The paper had come off the board and basically glued itself to the CDs. Two of the three were unreadable and unrepairable and the game is from the time when P90s were shit-hot so ebay was just about my only recourse.
Anyway the game arrived and these CDs were also unreadable. (Yes I tried in several CD-ROMs and my DVD-ROM.) Out of all the auctions over the past 5 years or so, I was ripped off for USD$10. Not a bad track record at all. I was able to read the CDs recently (I don't know if these were my original 3 or the auction 3, but it doesn't matter, they read in my new notebook DVD-ROM) and now I have one of my all-time favourite games again.:-)
I agree with you that if you have doubts, use escrow. 3-5% really isn't that much to pay for the insurance against getting ripped off. However saying that you're one of the lucky few is just plain fear-mongering. Ebay works for many, many people.
You said yourself that postgres is, in fact, slower than MySQL. There's a lot of good reasons why it's slower. An enterprise-level database needs certain features (which MySQL lacks) which will always cause a performance hit.
You're quite correct. However, and as I'm sure you're aware, PostgreSQL is oftentimes faster than MySQL when you're doing anything other than simple inserts and selects. If you'll read my original post again you'll see that I was upset when you didn't justify the "slower" than MySQL; you just blanket-statement said that it was slower, which is often taken as "always."
What I don't understand is why you think I'm the one walking on eggshells, or if I'm trying to convert you to PostgreSQL. All I was doing was calling you to task on your statement. You say you've got all this database experience so I'm sure that we're just arguing over semantics here. (by the way, I do thank you for keeping the argument civilized, it's rare on/.) MySQL is faster than PostgreSQL for the simple stuff. We both agree on that. PostgresSQL is taken more seriously than MySQL because of the features; I think we both agree with this too. And finally, PostgreSQL is faster than MySQL when you are doing any "real" database work (more than just simple inserts and selects on simple tables); I think we both agree on this as well.
As far as my resume goes: so what? I have enough relevant experience to discuss these matters and it seems that we're just arguing over nothing anyway; does a 30-year vertran have anything more important to say than a 3-year programmer? We're not talking about something where vast differences in experience make much difference, if at all.
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i opened up an 80kb xls file (it had one sheet with about 600 rows and 3 columns of voltages values from a picoscope, and then a graph on those values on the same sheet)
That's interesting; I was having trouble with an electronics-related graph too. In my case it was about 8000 rows and 28 columns of data with the related graph. (simulating a cycloconvertor on a three-phase motor)
Maybe it's largish graphs which cause the trouble; I have a similar file without a graph and it comes right up.
The main thing that matters to most people in an MS Office replacement is how well it reads and writes MS Office files. And that's, unfortunately, a moving target.
Agreed on both points. My experience with 641C (win and linux) is that it reads and writes Office97/2000 files with ease. Really large excel files it barfs on, but your normal .doc with graphics, "normal size" xls files, etc. all work great. I was really surpised at how well it writes the files, too.
And I don't understand the concept of PGP Sigs either.. How does that prove anything? What's to prevent me from smacking a PGP Sig on my email? Does anybody verify those?
I use KMail; it has very nice GnuPG integration, the only missing feature is for *it* to go through and encrypt my attachments instead of making me do it. At any rate, any email with a PGP sig is automatically checked and since I have the colour bar enabled signed messages with keys I trust (and that pass) are in a green border. Good sigs with keys I don't know/trust are in a yellow border and bad signs are in a red border. Very eye-catching and very nice.
I generally sign messages (not encrypt) if I want to give the person on the other end a way of verifiying that what I sent didn't get altered. I encrypt when I don't want anyone else reading it. It's perhaps a subtle difference, but I use it quite often.
It actually takes longer than 20 minutes if you think about it.
I did think about it. Bad hardware can happen on brand-names, too, and you're still out the time to get it replaced. Week-long delays happen with brand-names, too. I fail to see how this is a non-brand-name problem.
I stand behind my time of 20 minutes; if you've got all the hardware and none of it's bad (not that hard to do, really, but sometimes you get screwed), it takes no longer than twenty minutes to get the hardware into the case and get the screws done up.
disc imaging tools such as ghost don't have anything to do building a computer from scratch.
I think it is you who is missing the point.
How long does it take you to assemble a computer? About 20 minutes, tops? Thought so. Now how long does it take you to take that fresh Win2k install and run over to windowsupdate.com a half dozen times, rebooting after every one? Now install Office, Citrix, the in-house apps, set up the email software, grab the templates, etc.? Thought so. The time wasted is in software installation, not physical computer assembly. Buying a computer from Dell or building one from off the shelf parts is inconsequential.
You forgot about the killer hidden cost: labor.
And you are forgetting the tech support center's secret weapon: automation.
The crew at the company I work for can do a Win2k install by installing a CD, attaching a network cable and powering up. About 90 minutes later is a full standard 2k install, including all the apps and service patches and whatnot we've standardized on. If we had exact hardware across the board we could Ghost it even faster.
That $300 labour charge is only incurred when you have to babysit the install. Hell even my Slackware-based firewall installs go in in about 15 minutes now because I use custom tagfiles and a few of my home-rolled packages.
I find it interesting that out of several paragraphs of diatribe, a single phrase, with the magic word "union" in it, generated the string of responses, while the rest of the message seems to have slipped under the radar.
I was wondering if someone was going to point that out. I was reading the threads and your comment stuck out, and yes it was partly because of the word 'union.' It seemed to try and offer that the only way to avoid a real-life Alien environment is through your union badge. That and the insinuation that people (specifically Americans) who oppose unions are somehow pampered.
I'll be the first to admit that the word 'union' has some very negative connotations. Hell with the Canadian Auto Workers and OPSEU (Ontario Public Servants), the Teacher's Union and so on it's hard not to equate the word 'union' with 'old boy's club' -- everytime I see or read about a union it's in a negative connotation.
Now the idea behind unionization is a good thing; don't get me wrong. However a true union is about as hard to achieve and maintain as a true communist society. People are lazy and no matter how many rules you try to circumvent this, you'll end up with a system designed to pamper people at the top.
The fundamental irony of the situation is, most of the people here who are "free agents" working for the Man, can't see that in the Cave, their shadows are just as chained as the poor savages' are.
I can faintly see your point here but I'm afraid most of it is lost on me due to the metaphor; can you make it a little clearer for me? I have the sneaking suspicion that I do agree with you. :-)
Pampered Americans--those who cheer scabs over unionization--are reaping the whirlwind they've sown.
That's funny, because I see it the exact opposite.
What union values skill over seniority? What union congradulates effort over doing the minimum? I can't think of a single one. It's the unions which promote pampered "Americans" -- I would call them pampered employees, not the ones who refuse to work for such an assinine old-boys club.
The higher voltages is how it gets through all of the distance.
Incorrect; the voltage is only used to power repeaters and the CPE; the actual data transmission is done with low-voltage signals. If you increase the voltage swing or push more current, you end up increasing crosstalk and that brings you bigger troubles, which is why they use repeaters in the first place. It's the use of repeaters which give you the incredible distances that T1/E1 circuits can span, and the repeaters rely on the static -130VDC on the line.
Fibre-optic transocean lines do the same thing. You don't want to cut through a long-haul fibre line because they have thousands of volts across a couple of their internal metal layers to provide power for the ocean-floor optical repeaters.
While most repeaters take the -130V provided across the T/R and generate their own internal power supplies from it, some types of repeaters will take a -48VDC power source and regenerate the -130VDC for the next 50km or so, just as the CO-end equipment does. The -130VDC is current-limited (you're running on thin wire remember) and as such it just doesn't go all that terribly far. Powered circuits are only there to make life easy in remote locations (you don't need power handy), not to make the signal stronger. That's what regeneration and repeaters are all about.
That's odd. Perhaps HDSL runs differently, but the references say that a T1 should run at 2.7-3.3v, from AT&T publication 43801.
That sounds like a DSX1 spec; is that publication online? A quick google check find shitloads of references to it. :-(
You have a reply from djweis which says it's the voltage that cuts through the distance; this is untrue. The voltage is only used to power repeaters and the CPE; the actual data transmission is done with low-voltage signals. If you increase the voltage swing or push more current, you end up increasing crosstalk and that brings you bigger troubles, which is why they use repeaters in the first place.
Consider SDSL; not powered, and the range is similar to a standard HDSL2 circuit -- with HDSL(2), you can add repeaters since the line is powered; I can't do that with my SDSL circuits. It's a simple cost/distance tradeoff.
Consider that most COs run on -48v. To get 130v, they need to multiply voltage 2.7083 times. To get -3v(avg of 2.6-3.3), divide -48v by 16.
The electronic specs are not derived by easy to multiply/divide ratios like most things in the computer industry. The -130VDC is generated by the CO equipment using a simple boost regulator, which in turn runs off of the -48VDC float-charged lead-acid batteries you mention. I can create a 3.3V regulator or a 3.45V regulator with any input voltage; the real world is analog, which is why I love analog electronics design. :-)
I'm not really sure what you mean by this. Clock is regenerated by the remote end points of a DS3. There is no clock information carried through the circuit at the DS1 level.
You're right, they're re-clocked. I had to review the DS3 aggregation notes from Cisco. It's DS3s which have the slop bits, I don't think DS2s do this (they re-time the DS1s) -- I've never really worked with an actual DS2 so I don't know for absolute sure.
No, a DS3 is a completely different beast, with its own framing,coding, and timing rules.
That's what I was getting at; the DS3s (well the ones which are used to aggregate anyway) have all kinds of funky things going on inside but none of it is really all that interesting (at least not to me).
Um, no. Voltage supplied at the CO is completely determined by how many repeaters are on the line. You should end up with something like 12 volts at the CPE. -130VDc at the CPE would burn up just about anything you put on it, and would definately screw up a sinsitive test set.
This is incorrect. I just measured across the HDSL circuit here. -126VDC, no repeaters that I know of (3km circuit). Circuits in parallel (essentially what we have here) have equal voltage across them. Having to engineer the voltage for every circuit would be a royal pain in the ass. Actually for fun, take your HDSL CPE end, and take a good autotransformer and diode bridge. Connect the diode bridge + and - to T and R (polarity doesn't matter) -- now slowly bring up the autotransformer. The CPE end won't even light up until around 85V or so.
The guy at the telco almost certainly does NOT know how this stuff _really_ works. I've had to explain alarm codes to more than one "senior engineer". DON'T let him get off the phone. If he doesn't have a test set, hold on the phone until he does. Escalation is your friend.
haha, yes you are very correct here. Find someone and find some way to get their pager, cell and office numbers. And hold on to them because a good tech is very hard to find.
Looks like inerresting geek food.
(almost) Everything you Need to Know About T1s
Ancient tech, dating back to the '60s D1 circuits. I believe there was an F1 as well which used frequency-division multiplexing (i.e. what cable does) instead of time-division multiplexing. That's a real pain in the ass because the filters get very complex, and time-division multiplexing is dead-simple these days.
Your line between your house and the CO is very simple. It's a pair of twisted copper wires with some control voltage singalling (-48VDC on-hook, ~-8VDC on-hook, ~90VAC ring). When it hits the CO though it gets filtered (400-4000Hz) and digitized (PCM I believe) at 8 bits/8kHz and stuffed into a channel on a T1 if it's heading out to another CO.
These days you usually have equipment between the FXO and the switch which strips off the high frequency data and gives that to a DSLAM/RedBack/etc. but this is about voice.
A single voice communication channel is referred to as a DS0 and codes at 64kbps (8 bits * 8000 samples/sec). There are 24 DS0s in a DS1 (the data specification of a T1 is a DS1). Every DS1 frame has a framing bit. So 24 * 8 + 1 is 193 bits. Those 193 bits are sent 8000 times a second to give you your raw DS1 speed of 1.544Mbps. The frame is reserved though so you really get a useful bandwidth of 1.536Mbps.
In the olden days T1 circuitry required the frame bit to always be a '1' to maintain sync. These days the endpoint circuitry has no trouble keeping sync and the frame bit is used for "out of band" signalling. You figure 1 free bit 8000 times a second, that's a nice 8kbps of "free" information. This OOB channel is used to talk to the remote end to do things like loopback, QoS checks, etc. since it does not interfere with the data travelling in the 24 individual DS0 (data) channels. Pretty neat trick.
Now the actual electrical signals travelling those distances aren't 0v and 1v; it'd be impossible to get any data across. One of the first methods of electrically transmitting the data was AMI - Alternate Mark Inversion. A 0 (space) would be sent as no pulse, and a 1 (mark) would be sent as a pulse in the opposite direction of the last pulse. This kept the net DC voltage on the line at 0V (important for clock recovery), and simple flip-flip circuitry could be implemented to detect a bipolar violation (two consecutive pulses in the same direction).
Back when T1s were used ONLY for voice, nobody had to worry about long strings of 0s since it was statistically impossible to keep a PCM-coded voice channel at absolute zero, and the forced-1 state of the frame bit kept the framer in sync. Nowdays though T1s can carry data and it is easily possible to have long strings of 1s or 0s. Something had to be done.
With a long string of 1s you get a long string of "+1 -1 +1 -1..." (alternate pulse for each mark, remember) -- no problem. However a zero was coded as the absence of a pulse which meant that a long string of zeros would tend to have the clock sync drift since there were no pulses to sync to. B8ZS was born.
B8ZS (Binary 8 Zero Substitution) used a trick already used in low speed, short-haul communications such as RS232: escapes. A run of 8 zeros is sent as a specific error: "+1 + 1 0 0 -1 -1 0 0." The circuitry on the other side would see two BPVs (Bipolar Violations) in that specific pattern and instead of flagging an error, it would spit out 00000000. DS3s do the same trick with B3ZS. (aside: DS3 = 7 DS2 = 4 DS1, or 672 phone lines on a pair of coax cables)
Let's skip back to voice for a second. Remember how you have 24 voice channels being sent in a T1? Well as described, there is no way to tell if the line is on-hook, off-hook, ringing or busy. The solution was to steal a bit from each channel every so often and use that bit to represent line state. Since you're actually pissing around with the data, it's called in-band signalling, and specifically here, robbed-bit signalling.
What the telcos did was design a new framing system that used 12 DS1 frames as it's frame. Take 12 of those 193 bit frames and ear-mark #1 and #6. Now when Frame #1 comes along you will ignore whatever the LSB was for each DS0 and instead inject an "A" bit. And when #6 comes along you will do the same but inject a "B" bit. This big frame (12 DS1 frames) became known as the Super Frame.
What a normal DS1 frame looks like: (F = frame, A = A bit, B = B bit, 0-7 = PCM-coded voice traffic)
And for DS1 Frame #1:DS1 Frame #6:See how each channel gets an A and B bit?
What they did with the A and B bits was inject line state. 2 bits = 4 states. Now the CO can give you a busy signal or a ringback tone.
The telcos didn't stop there; they went on to give us the Extended Super Frame -- 24 DS1 Frames where every 6th frame has the LSB of the DS0s robbed to give you A, B, C and D bits. Most implementations just have the C and D bits mirror the A and B bits for now, but now you have 16 states to describe each channel in a DS1. This type of in-band signalling is known as robbed-bit signalling and is the reason you're at 56kbps for dialup. The modems actually do try and sync up to the DS1 framing and detect the robbed bit signalling when they trainup but really it's not going to get you much more speed to try and code at 64kbps 5/6th of the time and 56kbps 1/6th of the time. This robbed-bit signalling is only used on POTS; in data it's unnecessary because with ISDN your control info is in a separate D channel and for channelized-T1 it's not necessary.
I always feel like I'm talking about wrestling when I talk about SupaFrames and Extended SupaFrames :-)
Voice is always channelized; there are discrete conversations that have nothing to do with each other jammed together and transmitted as a group. Data T1s can come in channelized and unchannelized varieties. Basically it is used to group voice and data on a single T1, or, like voice, to group unrelated data communications together in an aggregate link for more efficient transmission.
Say you have a T1 between two offices and you want a 128bps link too. Well each DS0 is 64k, right? So they can take two DS0s and "split them off" for data, passing the other 22 for voice calls between the PBXes or KSUs or whatnot. Or if you want two 256k data links to two different areas; it can be done with one physical T1 to the CO, and then two from there to the locations. That's all that channelizing is about; aggregating datastreams into one connection.
Oh yes, ISDN. You'll recall that ISDN BRI is 64kbps. Guess what? An ISDN B channel is just one DS0, with the signalling occupying part of a 4kbps D channel. You can get fancy with something called Non-Facillity Associated Signalling which lets you cluster up to 8 DS1s' worth of D channels into a single B channel; That's right, with the right equipment termination you can combine up to 191 B channel control signalling into a single 64kbps D channel. (I don't think it's called a D channel anymore but I'm not sure on this.) -- dialup ISPs use it to try and regain lines when using PRIs, since a normal ISDN PRI is 23 B channels and a D channel (i.e. you lose a DS0 to signalling).
I briefly mentioned DS2s and DS3s. A DS2 is just an aggregation of 4 DS1s. The data bandwidth is not exactly 4*1.536mbps (frame is stripped out) because there are some slop bits set aside because the individual T1s coming in will not be synchronized and the slop bits take care fo that. It's the same with DS3s, which are made up of 7 DS2s. Not really exciting, because all the work was done at the DS0/DS1 level. :-)
Electrically, a DS1 is usually sent as an HDSL circuit these days; there really aren't any T1s to speak of anymore. DS = Data Specification (IIRC), where a T1 is just a DS1 with the electrical spec glued to it. Normally you have -130VDC on the line (supplied by the CO end) and the remote end (and any repeaters) get their power from the line. Pretty nifty. You can go up to 650 feet without powering the circuit if I remember correctly; unpowered DS1s are usually refered to as DSX1s.
Troubleshooting-wise you don't run into much these days. The CPE and CO ends almost always have serial ports and you snap on a laptop and ask it what's wrong or set up loopbacks and so on. The old days of having one end in a hot location and the other in shade and having that cause temp-related sync issues are long past.
So, there's almost everything you need to know about T1s. No need to buy a book that goes into the same detail. :-)
Lack of MSN Messenger is solved by grabbing Psi, a kick-ass jabber client. (Best I've used on Win32 or Linux).
I've never had trouble with my X Server bombing, but then again I've compiled my own XFree86 4.1.0 from source (not sure why I did it originally). Your CD Creator is a problematic one though, but it is coming.
As far as file sharing goes, I just use LimeWire's Java client. It's actually not too bad with the IBM Java compiler. You're right on when it comes to media though, although this too is coming.
KDE3 from CVS simply rocks, and if you don't want to compile it all yourself just grab the latest 3.0 beta; it's not far off from the CVS right now. I've been running Slack on my notebook for almost two years now, trying both Win4Lin and VMWare for the Windows things I need. If Win4Lin's support didn't suck so hard I'd have stuck with them but now that I only use Windows for the P&E Micro flash tools and some in-house Win32-only software, I hardly need to look at the Start button anymore. WindowMaker with KDE is a very nice combination; there are only two things weird. Klipper must be running or you get some very strange clipboard operation, and Java windows do not sit in the Konqueror "page" -- they are created as new toplevel windows.
All in all I tend to agree with you that Linux is almost ready. Almost. KDE has come a LONG way; it *is* ready for corporate offices but not for home users; I can deploy OpenOffice and KDE on anyone's workstation here and almost not have them notice. :-)
If I'm in public somewhere, I'm not leaving my laptop unattended.
actually what I do whenever I get a new laptop (this is my third, none stolen, just upgrades) is to remove the hard drive retaining screw; the drive is usually in some kind of carrier that is connected to the rest of the laptop by a single screw. Whenever I go somewhere and I don't want to lug the laptop with me, I pop out the drive. Laptops are easily replaced and are insurable. Backups I have but it's still a pain in the ass and if I'm out for a few days the work isn't backed up. The data loss is far worse than the actual theft.
If there's one thing I hate, it's Faq-o-Matic. I have never been able to get decent information out of such a mega-hyperlinked irritatingly-coloured monstrosity as Faq-o-Matic. That includes OpenLDAP's FAQ-o-Matic, Amanda's FAQ-o-Matic, Lynx's FAQ-o-Matic and FAQ-o-Matic's own FAQ-o-matic. Clicking a hundred links to get to a single paragraph that almost, but not entirely completely fails to answer the question is more annoying than not having an entry at all. And why does every FAQ-o-Matic seem to be hell-bent on experimenting in shades of puke for the colour scheme? Lynx's FOM doesn't follow this trend but damn near every single FOM on the planet is butt-ugly in addition to being terrible to navigate.
Provide FAQs in plain, easy to read HTML or text. Screw FAQ-o-Matic.
What I'd like to see is something along the lines of some kind of LRU which gently starts swapping data back into memory from swap when memory becomes free. There's nothing like having VMWare sitting in swap since you stopped using it an hour ago to do some other work and then jumping back and having to wait the 5-10 seconds of heavy disk activity to resume work there.
As for those saying "don't use swap at all" -- that's crazy talk. I'd rather have an app or two go to swap instead of being outright killed by the VMM when it needs an extra meg or so. If I'm not mistaken Linux tends to pick the big memory eaters to dump to swap over the little guys so if you start a compile... there goes VMWare... or your IM client... or Konqueror... lots of fun. :-)
He never said that it was an innovation of Windows. You did.
Which is exactly why I didn't say he did. I wasn't aware of the searches abck in Netscape 4 though. Thanks for the info.
The Windows XP 'powertool' has a very useful feature that allows you to enter a shortcut for a search engine. So if I type 'g privacy' it sends off a search to Google for 'privacy'.
Not a personal attack, but is this supposed to be an innovation of Windows? Both Konqueror and Opera have had this for quite some time now.
f you replace the openssl while SSH is running it will detect the version change and kill all running sshd sessions. Then you'll have a half installed openssl and not be able to start sshd.
Not entirely true; I had one server do this to me, but the six others that I upgraded work fine... update openssl, update openssh, kill running sshd parent, run new one, verify, exit. no problems.
If anyone can exlain why this one system may have done that, I'd appreciate it. It did this tlast time around too. :-(
OpenBSD is still right with her claim.
I don't think so... IIRC there was a remote root exploit in ssh < 3.0p1 which caused me to update my systems, and now this.
you mean the one that requires you to set up 3 accounts for the client, 3 accounts for the server, and comes with its own inetd replacement?
You forgot the part about the code being totally undocumented (including no descriptive variable names whatsoever) and that it will only securely talk to djbssh clients since ssh is a useless tool of a protocol that should have never been passed as in RFC. :-)
qmail is an awesome program. Too bad it's almost impossible to understand the code. :-(
That's because until version 3, Qt had a broken implementation of the X clipboard. With the advent of Qt 3 and KDE 3 it is expected that we will finally have a unified clipboard across X applications. That will happen in, say, a month.
I forgot to mention: I am running KDE3 CVS. Trust me, it's a big improvement, but still two clipboards. :-)
I vaguely remember reading that it would come with two options: standard linux cut&paste or windows-like cut and paste. How can you complain against options like that?
Easy; unless you're in a totally KDE environment, you get a mix of the two. I live with it every day on this notebook. KDE for almost everything, OpenOffice 6 for office, and WindowMaker and aterm pulling up the rear (well Citrix is in there too). I have *two* clipboards and *both* cut and paste methods... I've gotten used to it but it was frustrating for a while. :-)
My advice to all of you remaining Ebayers... please, use Escrow. I was one of a lucky few.
Lucky few my ass. It's the unlucky few who make the most noise. How many successful auctions does ebay have? Uh huh, and now in how many of those is the seller/buyer scammed? Ok, that's what I thought.
I've bought well over USD$50k of product via ebay over the past 5 years or so. Cisco access servers, mostly, but there has also been notebooks, routers, switches, electronic design gear (meters, oscilloscopes, logic analyzers etc.), manuals, software and my wife's SLR camera. No shit. The only time I used escrow was for an order of 6 Palm Pilot Vxes with keyboards and travel cases, but that was because that particular auction felt "funny".
I've only been ripped off once; I won an auction for the game Drowned God. It's a three-CD game in which the CDs come in a boxboard holder; I had lost my set and found them years later in the garage in a pool of water. The paper had come off the board and basically glued itself to the CDs. Two of the three were unreadable and unrepairable and the game is from the time when P90s were shit-hot so ebay was just about my only recourse.
Anyway the game arrived and these CDs were also unreadable. (Yes I tried in several CD-ROMs and my DVD-ROM.) Out of all the auctions over the past 5 years or so, I was ripped off for USD$10. Not a bad track record at all. I was able to read the CDs recently (I don't know if these were my original 3 or the auction 3, but it doesn't matter, they read in my new notebook DVD-ROM) and now I have one of my all-time favourite games again. :-)
I agree with you that if you have doubts, use escrow. 3-5% really isn't that much to pay for the insurance against getting ripped off. However saying that you're one of the lucky few is just plain fear-mongering. Ebay works for many, many people.
You said yourself that postgres is, in fact, slower than MySQL. There's a lot of good reasons why it's slower. An enterprise-level database needs certain features (which MySQL lacks) which will always cause a performance hit.
You're quite correct. However, and as I'm sure you're aware, PostgreSQL is oftentimes faster than MySQL when you're doing anything other than simple inserts and selects. If you'll read my original post again you'll see that I was upset when you didn't justify the "slower" than MySQL; you just blanket-statement said that it was slower, which is often taken as "always."
What I don't understand is why you think I'm the one walking on eggshells, or if I'm trying to convert you to PostgreSQL. All I was doing was calling you to task on your statement. You say you've got all this database experience so I'm sure that we're just arguing over semantics here. (by the way, I do thank you for keeping the argument civilized, it's rare on /.) MySQL is faster than PostgreSQL for the simple stuff. We both agree on that. PostgresSQL is taken more seriously than MySQL because of the features; I think we both agree with this too. And finally, PostgreSQL is faster than MySQL when you are doing any "real" database work (more than just simple inserts and selects on simple tables); I think we both agree on this as well.
As far as my resume goes: so what? I have enough relevant experience to discuss these matters and it seems that we're just arguing over nothing anyway; does a 30-year vertran have anything more important to say than a 3-year programmer? We're not talking about something where vast differences in experience make much difference, if at all.