User: Forever Wondering

Re:NIH?

On: BBC Reveals Its New Microcomputer Design

And, once again, they've come up with an oddball, just for the sake of doing it.

The 1980's attempt was like an anemic version of an Apple II or Commodore Amiga. The BBC museum has been begging for volunteers to fix/maintain their 1980's computer systems. 30 years from now, they'll have the same problem with this new system.

The current [proposed] system is so watered down that any student will be bored within 1-2 years. A Raspberry Pi would delight well into adulthood. Also, a young adult will have a better time getting a job if they can claim Raspberry Pi experience [Pi's are starting to be used in real world applications like industrial controllers] as opposed to a "toy" system.

Given that the BBC is part of the UK gov't, perhaps they rejected the Pi because they couldn't convince the foundation that adding the anti-terrorist/surveillance tech [that Cameron has been yakking about] was a good idea. Or, that the Pi was "too powerful" for school children and could be used by terrorists ... Just sayin' ...

Re:kessel run

On: Han Solo To Get His Own Star Wars Movie Prequel

Isn't a parsec a unit of distance and not of time?

Re:You are Doomed

On: Ask Slashdot: Best API Management System?

If you're old enough to remember the micronova [I'm a former DG software engineer and I wrote code for it], you can probably remember the PC "turbo" switch. When IBM realized that PCs were outperforming their mid-range business systems (AS400???), they changed the BIOS to prevent boot if the PC ran too fast. Hence, the turbo switch: Run slow until BIOS is done, push turbo switch to get faster clock speed.

That was IBM's first attempt to control [PC] turf. The second came with the micro channel architecture (MCA). Their proprietary licensing caused clone mfgrs to revolt and form a standards organization that produced the ISA bus. Eventually, IBM lost control of a market it created.

Same thing is happening with MS. Tried too hard to map everything back to Win*, even for mobile. Now, they're late to the party and are open sourcing .NET--but it's too late. Mindshare [among developers] has already headed to Android/IntelliJ/etc.

Megaharm

On: Ask Slashdot: What's the Harm In a Default Setting For Div By Zero?

System wide setting? Most other programs don't want it. What you want is a function you can call at the start of your program: no_div_by_zero_exceptions_in_this_program().

But, that is a bad idea (tm) because the programming language/system doesn't know the context. That is, what you intend if div-by-zero occurs on a line-by-line basis. That's why you have to have explicit checks:

if (y != 0)
    z = x / y;
else
    z = ...; // what you want: x, 0, inf, -1, throw exception, abort program, whatever

But, this is just a single check out of the things a program has to check for:
- null pointers
- array bounds
- insane/wrong values (e.g. a person's age shouldn't be a negative number)
- object in wrong state for operation to be performed (e.g. trying to do a database operation when the DB handle isn't locked)
- ...

Also, drawing on the recent Linux raid0 problem [where FS corruption was happening], they had something akin to:
    sector_offset = absolute_byte_position / sector_size;
If sector_size happened to be zero (a programming mistake), silently returning zero here would corrupt the disk/file.

You've been programming for 20 years? Well, junior [I've been programming for 43--sigh], you've still got a lot to learn. And the fact that you didn't see the harm before you posted proves that.

Mork's son ...

On: Ask Slashdot: What Happens If We Perfect Age Reversing?

... born full grown and aging in reverse [just like all Orkans]

Re:It's RAID 0

On: Linux 4.0 Has a File-System Corruption Problem, RAID Users Warned

Based on the commit fixes, it's in a function called raid0_make_request, which is only used in raid0.c
raid 10 is in raid10.c, so it doesn't use this function.

The bug is based on the fact that a macro "sector_div" modifies it's first argument [and returns the remainder]. I've removed the obligatory backslashes for clarity:

# define sector_div(n, b)(
{
        int _res;
        _res = (n) % (b);
        (n) /= (b);
        _res;
}
)

This is used in some fifty files. Some just want the remainder [and they don't want the first arg changed so they do]:

sector_t tmp = sector;
rem = sector_div(tmp,blah);

This is effectively what the code wanted, but the actual fix was to do a restore afterwards:

sector_t sector = myptr->sector;

...
rem = sector_div(sector,blah);

...
sector = myptr->sector;

... // use sector [original value only please ;-)]

The last line to restore sector with the original value was the fix.

They should do a full code audit as their may be other places that could be a problem. I've reviewed half the files that use this macro and while they're not broken, some of the uses are fragile. I paraphrase: "sector_div considered harmful"

What they really need are a few more variants which are pure functions that could be implemented as inlines:
rem = sector_rem_pure(s,n)
s2 = sector_div_pure(s1,n)

Or, a cleaner sector_div macro:
sector_div_both(s,n,sector_return,rem_return)

Re:North Pole

On: The Brainteaser Elon Musk Asks New SpaceX Engineers

Yes, they do go on forever. I stopped at 100x for the sake of brevity and slashdot eccentricities (e.g. when I put only one loop per line, /. complained about "lines are too short"). At 100x, the south lat (after going one mile south) is 8 ft, 4 in (99x was 8 ft, 5 in). Eventually, the program would need to use semi-infinite precision math (e.g. double wouldn't be enough). Also, I used a 2D approximation for the distance to pole rather than calculate the arc length [I was too lazy/tired]. Still, pretty close, and good enough for illustration purposes.

#!/usr/bin/perl
# tbin/elon -- elon musk's brain teaser

#pragma pgmlns

master(@ARGV);
exit(0);

# master -- master control
sub master
{
my(@argv) = @_;

$fmt_big = "%.12f";

$M_PI = 3.14159265358979323846;
$M_PI_2 = $M_PI * 2;

# circumference of the earth
$Ce = 24901.0;

# radius of the earth
$Re = radius($Ce);

$deg_per_mile = 90.0 / $Re;

for ($loopiter = 1; $loopiter <= 100; ++$loopiter) {
dolat($loopiter);
}

{
last if ($altflg);

$bf = $out[0];
@rhs = split(" ",$bf);

$bf = title($rhs[0],"loop");
push(@title,$bf);

$bf = title($rhs[1],"degrees S lat");
push(@title,$bf);

$bf = title($rhs[2],"dist to S pole");
push(@title,$bf);

$bf = join(" ",@title);
unshift(@out,$bf);
}

foreach $bf (@out) {
print($bf,"\n");
}
}

# dolat -- calculate for single latitute
sub dolat
{
my($loopiter) = @_;

$Cx = 1.0 / $loopiter;
$Rx = radius($Cx);

# distance from southern latitude to equator
$l = $Re - $Rx;

$deg_S = ($l / $Re) * 90.0;
$deg_N = $deg_S - $deg_per_mile;

$dist_to_pole_S = $Re - $l;
$dist_to_pole_N = $dist_to_pole_S + 1;

@lhs = _showdist($dist_to_pole_N * 5280 * 12);
prtf("%3.3dx ${fmt_big} %s mi, %s ft, %s in\n",
$loopiter,$deg_N,$lhs[0],$lhs[1],$lhs[2]);
}

# _showdist -- show distance in human readable form
sub _showdist
{
my($tot,$tag) = @_;
my($tgb,@elap_tgb);
my($modlhs);
my($cur);
my($bf);
my(@lhs);

push(@elap_tgb,5280);
push(@elap_tgb,12);
push(@elap_tgb,1);

Not to worry ...

On: Secret Files Reveal UK Police Feared That Trekkies Could Turn On Society

Trekkies always keep their phasers set to stun ...

Re:North Pole

On: The Brainteaser Elon Musk Asks New SpaceX Engineers

There are a number of southern latitute rings: See http://slashdot.org/comments.p...

Re:North Pole (South pole ring data)

On: The Brainteaser Elon Musk Asks New SpaceX Engineers

Here's the first hundred latitutes [I wrote a perl program--so it could never be wrong ;-) and I had to derive it]

loop degrees S lat dist to S pole
001x 89.973676291007 1 mi, 840 ft, 4 in 002x 89.975483447346 1 mi, 420 ft, 2 in
003x 89.976085832792 1 mi, 280 ft, 1 in 004x 89.976387025515 1 mi, 210 ft, 1 in
005x 89.976567741149 1 mi, 168 ft, 0 in 006x 89.976688218238 1 mi, 140 ft, 0 in
007x 89.976774273302 1 mi, 120 ft, 0 in 008x 89.976838814600 1 mi, 105 ft, 0 in
009x 89.976889013387 1 mi, 93 ft, 4 in 010x 89.976929172417 1 mi, 84 ft, 0 in
011x 89.976962029805 1 mi, 76 ft, 4 in 012x 89.976989410962 1 mi, 70 ft, 0 in
013x 89.977012579633 1 mi, 64 ft, 7 in 014x 89.977032438493 1 mi, 60 ft, 0 in
015x 89.977049649506 1 mi, 56 ft, 0 in 016x 89.977064709142 1 mi, 52 ft, 6 in
017x 89.977077997057 1 mi, 49 ft, 5 in 018x 89.977089808536 1 mi, 46 ft, 8 in
019x 89.977100376702 1 mi, 44 ft, 2 in 020x 89.977109888051 1 mi, 42 ft, 0 in
021x 89.977118493557 1 mi, 40 ft, 0 in 022x 89.977126316745 1 mi, 38 ft, 2 in
023x 89.977133459655 1 mi, 36 ft, 6 in 024x 89.977140007323 1 mi, 35 ft, 0 in
025x 89.977146031178 1 mi, 33 ft, 7 in 026x 89.977151591659 1 mi, 32 ft, 3 in
027x 89.977156740252 1 mi, 31 ft, 1 in 028x 89.977161521089 1 mi, 30 ft, 0 in
029x 89.977165972213 1 mi, 28 ft, 11 in 030x 89.977170126595 1 mi, 28 ft, 0 in
031x 89.977174012953 1 mi, 27 ft, 1 in 032x 89.977177656414 1 mi, 26 ft, 3 in
033x 89.977181079058 1 mi, 25 ft, 5 in 034x 89.977184300371 1 mi, 24 ft, 8 in
035x 89.977187337608 1 mi, 24 ft, 0 in 036x 89.977190206110 1 mi, 23 ft, 4 in
037x 89.977192919558 1 mi, 22 ft, 8 in 038x 89.977195490193 1 mi, 22 ft, 1 in
039x 89.977197929001 1 mi, 21 ft, 6 in 040x 89.977200245868 1 mi, 21 ft, 0 in
041x 89.977202449717 1 mi, 20 ft, 5 in 042x 89.977204548621 1 mi, 20 ft, 0 in
043x 89.977206549902 1 mi, 19 ft, 6 in 044x 89.977208460215 1 mi, 19 ft, 1 in
045x 89.977210285625 1 mi, 18 ft, 8 in 046x 89.977212031670 1 mi, 18 ft, 3 in
047x 89.977213703415 1 mi, 17 ft, 10 in 048x 89.977215305504 1 mi, 17 ft, 6 in
049x 89.977216842202 1 mi, 17 ft, 1 in 050x 89.977218317431 1 mi, 16 ft, 9 in
051x 89.977219734809 1 mi, 16 ft, 5 in 052x 89.977221097672 1 mi, 16 ft, 1 in
053x 89.977222409106 1 mi, 15 ft, 10 in 054x 89.977223671968 1 mi, 15 ft, 6 in
055x 89.977224888909 1 mi, 15 ft, 3 in 056x 89.977226062387 1 mi, 15 ft, 0 in
057x 89.977227194690 1 mi, 14 ft, 8 in 058x 89.977228287949 1 mi, 14 ft, 5 in
059x 89.977229344148 1 mi, 14 ft, 2 in 060x 89.977230365140 1 mi, 14 ft, 0 in
061x 89.977231352657 1 mi, 13 ft, 9 in 062x 89.977232308319 1 mi, 13 ft, 6 in
063x 89.977233233642 1 mi, 13 ft, 4 in 064x 89.977234130049 1 mi, 13 ft, 1 in
065x 89.977234998874 1 mi, 12 ft, 11 in 066x 89.977235841371 1 mi, 12 ft, 8 in
067x 89.977236658719 1 mi, 12 ft, 6 in 068x 89.977237452028 1 mi, 12 ft, 4 in
069x 89.977238222342 1 mi, 12 ft, 2 in 070x 89.977238970646 1 mi, 12 ft, 0 in
071x 89.977239697872 1 mi, 11 ft, 10 in 072x 89.977240404898 1 mi, 11 ft, 8 in
073x 89.977241092552 1 mi, 11 ft, 6 in 074x 89.977241761622 1 mi, 11 ft, 4 in
075x 89.977242412849 1 mi, 11 ft, 2 in 076x 89.977243046939 1 mi, 11 ft, 0 in
077x 89.977243664559 1 mi, 10 ft, 10 in 078x 89.977244266343 1 mi, 10 ft, 9 in
079x 89.977244852891 1 mi, 10 ft, 7 in 080x 89.977245424776 1 mi, 10 ft, 6 in
081x 89.977245982541 1 mi, 10 ft, 4 in 082x 89.977246526701 1 mi, 10 ft, 2 in
083x 89.977247057749 1 mi, 10 ft, 1 in 084x 89.977247576153 1 mi, 10 ft, 0 in
085x 89.977248082359 1 mi, 9 ft, 10 in 086x 89.977248576793 1 mi, 9 ft, 9 in
087x 89.977249059861 1 mi, 9 ft, 7 in 088x 89.977249531950 1 mi, 9 ft, 6 in
089x 89.977249993430 1 mi, 9 ft, 5 in 090x 89.977250444655 1 mi, 9 ft, 4 in
091x 89.977250885963 1 mi, 9 ft, 2 in 092x 89.977251317677 1 mi, 9 ft, 1 in
093x 89.977251740108 1 mi, 9 ft, 0 in 094x 89.977252153550 1 mi, 8 ft, 11 in
095x 89.977252558288 1 mi, 8 ft, 10 in 096x 89.977252954594 1 mi, 8 ft, 9 in
097x 89.977253342729 1 mi, 8 ft, 7 in 098x 89.977253722943 1 mi, 8 ft, 6 in
099x 89.977254095476 1 mi, 8 ft, 5 in 100x 89.977254460558 1 mi, 8 ft, 4 in

Re:bypass operation must be covered under ACA

On: Swallowing Your Password

Re: Nixon. Remember the bumper sticker "Don't blame me--I'm from Massachusetts"? I'm still screaming bloody murder about current state surveillance. Some may be necessary, but the amount being done far exceeds what is needed.

Also, 50 years ago, people were screaming about Medicare [with the same arguments about gov't takeover of healthcare]. Now, we recognize the comfort and safety net it has given our senior citizens to have good health care in their declining years when they need it the most.

Re:Not allowed under the ACA smokeing is the only

On: Swallowing Your Password

I'd double check this. Under the ACA, premiums are set based upon your age and your "zone" [effectively, your zip code].

bypass operation must be covered under ACA

On: Swallowing Your Password

The heart bypass operation must be covered under the ACA (aka Obamacare). Insurance companies can no longer discriminate based on pre-existing conditions and can no longer impose a lifetime coverage cap.

That is not to say that the implant idea is a good one for a number of other reasons.

Re:The 777 is unique in its vulnerability

On: Calling Out a GAO Report That Says In-Flight Wi-Fi Lets Hackers Access Avionics

I'm not Alanis.

Perhaps, ironic was an unfortunate choice of words, but I didn't mean it in terms of sarcastic/sardonic. There is an alternate definition:

happening in the opposite way to what is expected, and typically causing wry amusement because of this.
"it was ironic that now that everybody had plenty of money for food, they couldn't obtain it because everything was rationed"

(e.g. paradoxical, incongruous)

Shortly after 9/11 when they were first proposing armoring the cockpit doors, I remember thinking: "But, what if you have [a legitimate need] to get in there?". Hence, the irony for me. If the locked out pilot had access through such a maintenance port, he might have been able to override the suicidal co-pilot.

After GermanWings, there are new proposals:
(1) Europe adopting the U.S. policy of two crew members in the cockpit at all times [even if one is a flight attendant].
(2) Aircraft flight systems will [forcibly] take over flying the plane if they detect something [egregiously] unsafe--not merely warn the pilot.
(3) Allow a ground based pilot crew to take over flying the aircraft remotely (like a drone aircraft) if something is unsafe.
(4) Not allowing [as is presently allowed] a single person to disable the cockpit door unlock codes/keys.

Remedies (2) and (3) aren't limited to just a suicidal pilot. Hypoxia may overcome both pilot/co-pilot before they have a chance to switch to oxygen.

But, if people are screaming "beware of hackers" now, just imagine the hoopla surrounding implementation of (3). Although remote drone piloting is used by military drones, there have been some [unconfirmed] reports of nefarious people being able to take over drones.

Re:The 777 is unique in its vulnerability

On: Calling Out a GAO Report That Says In-Flight Wi-Fi Lets Hackers Access Avionics

This avionics bay access hatch vulnerability was recently reported on CNN [ironically, prior to the GermanWings disaster]

Had a fire--Here's what I did

On: Ask Slashdot: Best Medium For Storing Data To Survive a Fire (or Other Disaster)

I actually experienced the scenario you're talking about: fire in my apartment complex. Fortunately, nobody was hurt but several people lost all their possessions. Lucky for me, the fire only got within 90 feet of my place [while the fire was raging I was sweating bullets]. This was the one day I didn't have my laptop [which was my previous backup in case of fire] with me and I was out at the time.

I now use a 64GB USB stick that I carry on my keyring, so it's always with me. I also have one that's in the trunk of my car [under the spare tire].

Additionally, mailing the the USB stick to a family member or friend [one that you trust]. Also, get a safe deposit box. This can hold a full blown 4GB USB portable drive that can keep a lot more data. Because you stated that you only need 5GB or so, this makes the USB stick the ideal solution.

If you're paranoid, encrypt the backup.

Keep multiple disks of whatever variety and rotate them. That is, backup to disk A on Monday, disk B on Tuesday, etc. That way, if the actual backup process croaks the backup media (e.g. power failure during the backup), you still have other copies. This rotation also applies to trips to the safe deposit box and return mailings from your trusted friend with the older backup drives.

Of course, you can do the encryption yourself locally and send it to the cloud [as others have suggested]. Use multiple vendors in case one goes out of business. Actually, this may not work too well because of ISP datacaps and slow uplink speeds if you have a lot of data, not because of the cloud storage company per se.

Re:Hell No Hillary

On: Hillary Clinton Declares 2016 Democratic Presidential Bid

Cute animation, but you actually disprove your own point as one of the top search results was wikipedia. From the wiki entry, http://en.wikipedia.org/wiki/L... the Clinton, Carter, and Ford administrations each had two "scandals" in the executive branch. Most other [recent] republican ones had many more.

BTW, I didn't check the other search results because they appeared to be obscure_website_ive_never_heard_of.com and while wikipedia is far from perfect, I'd trust it [a bit] more than the others. Actually, I'd prefer a truly credible source like Wash. Post, NYT, CNN, LA Times, The Economist, etc.

Re:Obligatory

On: Rust Programming Language Reaches 1.0 Alpha

For example,

        Circle * foo() {

                Circle c1(5);

                Circle c2(10);

                return biggestCircle(&c1,&c2);

        }

We know that would be invalid, but a C++ compiler wouldn't see any problem. The Rust compiler, on the other hand, can see that the lifetime of the return object of biggestCircle can be no longer than the lifetime of either parameter.

If Circle is a non-trivial struct (e.g. has 50 elements in it), passing by reference might be done for efficiency [e.g. biggestCircle args are "const Circle *"].

A compiler shouldn't make an assumption because biggestCircle might be defined in a separate .cc file and might clone/dup its return value from its arguments or a combination of arguments. The invocation might be:
    x = foo(); ...
    free(x);

Or biggestCircle might return something only obliquely related to c1/c2. biggestCircle might compare c1/c2 and get the max, but then do a search within "the global list of geometric objects" looking for a match to the max value and return the global/persistent value [which would live on beyond the outer return].

Rust would squash this even though it's perfectly valid [and desired].

Re:It's in the image

On: Human Eye's Oscillation Rate Determines Smooth Frame Rate

The mayonaise you like is the mayonaise you grew up with ...

Films are shot at 24 fps, but displayed [in theaters] at 48 fps, each frame is displayed twice: f0, black, f0, black, f1, black, f1, black, f2, ...

According to one study, when test audiences were shown true 1-to-1 48 fps film, they actually preferred the 24 fps.

The same is true for audio. Those that grew up on 128 kbps .mp3's preferred that over higher fidelity formats.

The human optic nerve has [surprisingly] low bandwidth. I worked for a company that developed a [now shipping] video product that models the human optic system and removes detail that the human eye would not see. This allows better compression without sacrificing video quality. In A/B testing of original [uncompressed] video sources vs. the detail reduced video, test audiences preferred the detail reduced video. It was considered "cleaner" and "more pleasing".

Re:from the what-until-they-get-a-load-of-this dep

On: Amazon "Suppresses" Book With Too Many Hyphens

According to Merriam Webster, "hit man" should not be hyphenated ...

star trek: phase ii

On: Behind the Scenes With the Star Trek Fan Reboot

http://en.wikipedia.org/wiki/S...

Re:C is very relevant in 2014,

On: How Relevant is C in 2014?

Perhaps C's greatest weakness is that it places too much trust in the coder, where other languages don't.

Perhaps C's greatest asset is that it assumes that the coder is not an idiot, whereas other languages do.

Re:What about long-term data integrity?

On: How Intel and Micron May Finally Kill the Hard Disk Drive

Engineers in Taiwan have supposedly solved the cell wearout problem. See http://phys.org/news/2012-12-t...

Re:First step is to collect data.

On: Ask Slashdot: How To Unblock Email From My Comcast-Hosted Server?

All the rejection messages point to your systems being affected in some way. The "agent" may be establishing an SMTP connection that doesn't need authentication (e.g. it connects directly to yahoo's inbound SMTP port for a message to a yahoo user. Thus, it's not a relay as far as yahoo is concerned).

It could be bypassing anything you've already set up [or co-opting it in some way that you don't yet understand]. If your systems have been compromised, all the authentication credentials are available to the agent. The best way I know of to prove/disprove this is to set up a sniffer/router/blocker.

The rejections are based on [too] high message frequency, which tends to indicate that you're not on a blocklist [yet]. It's also not likely to be a policy change at a given mail recipient ISP since at least three started rejection at more or less the same time.

Having the ability to log/monitor/analyze traffic in general might be a good thing. What if it weren't just emails but DDoS or other attacks [which carry considerably more liability for your business]?

If you can track down some of the messages that got sent that had complaints attached to them, the delivery envelope may have some clues. For example, the specifics of the SMTP parameters used (ordinary SMTP or eSMTP, etc.) Perhaps contacting the mail abuse departments of yahoo et. al. and explaining what is happening may help. They could tell you how many messages are arriving from your IP address. Compare this against an estimate of what your users are doing. If your legit users haven't starting sending many more messages recently, but the ISP is seeing a huge uptick, this will be telling.

Since you've got [and are paying the extra money for] Comcast business class, they should be able to help with the traffic logging/analysis. Also, if the targeted ISPs are limiting based on an IP range, Comcast may be able to help in dealing with the ISPs. You may have to escalate this a level or two within Comcast's support hierarchy. Be sure to get a trouble ticket filed [if you haven't already].

Re:First step is to collect data.

On: Ask Slashdot: How To Unblock Email From My Comcast-Hosted Server?

Deferred: 421 RP-001 ...

Are you sure your systems haven't been compromised by spambots? Everything was fine two weeks ago [and had been for a while]. What's changed? ISP logs before and after may show something.

Can you set up a new system [with a different OS like linux, netbsd, etc.] that is a gateway between your current systems and your router/modem [would require a second ethernet port/card]. Have this system filter/monitor all traffic, looking for something suspicious.