Don't make this too hard. The PCI bus on a cheap motherboard is 32bits at 33Mhz, or a peak bandwidth of 132Mbytes/second. A 1X CD-ROM is 44.1Khz * 2 channels * 16 bits (2 bytes) or 176Kbytes/second.
If the PCI bus were perfect, it could drive a single 748X CD writer, or ten 74X CDWriters. It's not perfect, but you'll easily get more than half of the max bandwidth (assuming modern PCI cards). Since 32X is the fastest CDwriter available today, you can easily drive 10 of them with quite a margin.
If they're new CDwriters, they'll have protection against making coasters, so the penalty for running too many CDwriters, is they'll slow down.
If you're good with metal working tools, you can make a double wide case that can hold 10 drives. Plug a bunch of IDE controller cards into the PCI bus. Note: IDE cables are limited to 18 inches. So you have to do a little design work, before you start cutting metal.
If you're not into metal working, just take a few cheap PC's, max them out with CDwriters and network them with 100base-T ethernet cards. A little glue, and it will be like one big machine. This design can be expanded to hundreds of drives.
I'm assuming student labor, so you won't need a robot disk changer.
Seems accurate to me. Amazon choses to use low margins only where there is competition, and then only if they want to "win" in that marketplace.
The high price ebook business model isn't on a firm foundation, so there's little business reason to try and capture that market.
Ebooks will take off when the books get much cheaper, and the authors get to keep most of the "cover" price. Textbook authors often get less than 10% of the cover price on paper books.
Imagine if the author got $4 royalty and the editor got $1 on a $6 e-textbook, they'd both make more money per book, and the students would spend less per book. The intellectual property creators and consumers would win, and the middlemen, the publishers, printers, and distributors would need to find new jobs.
Alas, the publishers have lots of lawyers and are delaying this as long as they can.
they are continuing VR3 development -- but's not clear whether that means software or device development.
That means device development. Software development is being done by the user community.
Agenda Germany should concentrate on hardware, since that's not something that we can do by ourselves very well. I'd rather buy a mass produced Agenda with 16MBytes of RAM, rather than spend hours soldering.
They'll run into DSL's biggest enemy: reflections.
That's true for Cable TV, so Cable TV cables are already relatively clean.
This is probably one of the reasons they are focusing on cable TV. Most other existing wired technologies (phone, ethernet, speaker wires, etc...) tolerate reflections much better, so the infrastructure has a lot more of them.
I want the CD Writer facing backwards. I don't use anything else on the front of the system. Uptimes are in the hundreds of days, I don't use the powerswitch or reset button very often. I do want access to all of the connectors and the CD Writer.
It would be worth $20 to $30 to not need to get out the dremel and make my own rear facing drive bay.
The other choice is externally mounting the CD-Writer. That makes the whole system more fragile. More of a pain to move and to work on.
It's hard to run IDE cables externally, possible, but hard. SCSI CDWriters are either slower, more expensive or both. USB 1.1 is slower. Firewire and USB 2.0 are more expensive. Check pricewatch.com, $71 for 24x10x40x IDE, USB 1.1 is limited to 4X4X6X ($85), firewire starts at $144.
The managers at the big companies may be evil, but they aren't entirely stupid. As the new technologies come through, they reshape the business world. New technologies make some companies grow, and other companies fail. So, which movie companies shrank as a result of VCRs, and which ones prospered?
As we all know, VCRs helped most of the movie companies prosper. Now look at the executives. Video sales and rentals helped a bunch of executives climb the movie company corporate ladders. Which means turnover at the top.
The folks choosing to bring the lawsuits, might be afraid that their company will suffer, or more likely, they're afraid that they personally will suffer.
It's no big deal. Some comunications lines use 3 states, -v, 0v, +v. The 3 levels represent 0, 1 and same as the last bit. They use the third level so they change the voltage every clock cycle and thus only one frequency travels down the wire.
Naturally, such systems get enhanced so they can send more data at the cost of a little harmonic purity. For expample, they could get 50% more data through by using pairs of trits to send 3 binary bits. The 9th state would be used to prevent leaving the line at one voltage level too long. The real encodings are better behaved in the analog domain, and therefore more complex, but lookup tables for the trit to binary conversions take very little silicon.
For those who haven't memorized powers of three, if trinary logic, memory or signalling works better in some situation, 1 trit holds 1 bit,
2 trits hold 3 bits, 12 trits hold 19 bits, 31 trits hold 49 bits, etc...
Going the reverse is also very simple. If you have an algorithm that works better in trinary, store 1 trit in 2 bits, 3 trits in 5 bits, 5 trits in 8 bits, etc... You don't need special hardware.
If you've got more than a handfull of users, then you want RADIUS or something like it to authenticate users/systems as they connect.
RADIUS is just an authentication protocol, it doesn't provide privacy. Sript kiddies will have to pretend to be using systems that have active sessions. Ok, the script kiddie may not know what's going on, their scripts will have to pretend.
RADIUS may work, but you've still got to replace WEP.
You still want some schedule of full, and partial backups with some combination of on and offsite storage. You also want to use affordable media.
All the Unix backup tools can backup to disk as easily as to tape. Carriers to make ATA/100 disks removable cost about $10 each. ATA/100 disks are cheap per megabyte.
There are techniques to make the disks hot swappable, or use a dedicated backup machine that can be easily powered down to swap disks.
Most importantly! It's a restore system, not a backup system.
Nobody cares how great your backups are, if you can't do a restore when you need it.
I played with it for a while many months ago. After reading this Oreilly Net Article about it. The link is to page 2, because that's where the calibration stuff is.
This is how you can find out where all the pixels are pointing. I suspect there is code for calibrating intensities, but I didn't use it.
Avoiding traffic analysis is easy on a private line, use 100% of the bandwidth with fixed sized encrypted packets. Create a VPN. Multiplex the VPN with just enough zeros to exactly use the available bandwidth. Encrypt that data stream and send it with fixed sized packets. At the other end, decrypt, demultiplex out the zeros, and expand the VPN.
For added annoyance value, use random data instead of zeros.
You'll still want to armor the cable, put in a bunch of dummy fibers and many of the other things that were suggested.
The article also says An injection of water into the chamber helps cool the engine, and the steam generates
additional pressure to drive the engine. So it also needs a tank of water.
Hydrogen + oxygen burns to make pure water over a wide range of temperature and pressure. Dilute the oxygen and it takes more pressure. At some combinations of temperature and pressure, it'll also combine some oxygen with nitrogen and make stuff that isn't so clean.
At best, it's decades away from something practical for a car.
With DSL only the very first hop is dedicated to a single customer. Once your bits get to the central office, they share a pipe with other customers. If that pipe has less bandwidth than the sum total bandwidth of the individual customers, that pipe is oversubscribed. Likewise for all of the upstream pipes.
With a cable modem, the only difference is that the very first hop might also be oversubscribed.
A cable has a lot of bandwidth. That bandwidth is divided up into channels (on an NTSC analog system, channels are all 6Mhz wide, your channels may vary). Each internet cable box is assigned a channel (or set of channels, if channels only come in one size). Your next door neighbor's cable box might use a different channel, and thus not be in the same neighborhood.
Logically, a cable system is a tree, or set of trees, with the root of each tree at the cable company office, and the customers are the leaves. The thicker branches may run on fiber, they support more channels, and therefore more neighborhoods.
A wee tiny cable company may have a single T1 (1.5Mbps) line connecting to the greater internet, a large company might have several OC48 (2.5Gbps). The same is true for DSL providers.
ISP's either charge premium rates or they oversubscribe the service, or both. I don't see a primetime slowdown on my $180/month, 384K DSL line.
For some video editing tasks there are only two speeds, fast enough and not fast enough. There's no benefit in being able to read or write data 8 times faster than you need, rather than only 5 times faster you need.
Many motherboards only support a single 33
Mhz/32 bit(4 byte) PCI bus, that is only 133Mbytes/second. With 3 or more new fast ATA/100 drives (limit 1 per cable) and cheap IDE controllers, you can run out of PCI bus bandwidth.
Under the heading 3ware?, cymen listed some IDE RAID controllers that will work in a 66Mhz/64 bit PCI bus. The motherboards cost more, but the speed limit is 528Mbytes/second.
We use software RAID with IDE, because the main processor is 1.4Ghz or better and has access to 1 or 2 gigabytes of buffer memory. If you are CPU limited, it is much cheaper to get a dual CPU motherboard, than to get a fast hardware RAID system.
It's not just a hardware issue. Which OS or OS's do you want to support? A solution that works for Linux may not work on some flavor of BSD. You might even be stuck with one of the dozens of lesser OSs.
Some how, 12 or more volts has been shorted onto the 3.3 or 5 volt supply. If you look closely at the motherboard, you'll probably see heat damage around one trace on the motherboard. You may even be able to see where the damage starts.
Look for a loose screw or metal trash underneath the motherboard.
Capacitors blow up from too much heat, which for a DC power supply filtering capacitor implies too much voltage. Capacitors are in parallel with the power supply. Something put too high a voltage across the capacitors.
Unless I'm really confused, the highest voltage on the IDE connector is only 5 volts, and all of the pins on the IDE connector are either ground or are compatible with 5 volts. You can hurt the logic chips and the power supply by shorting stuff on the IDE connector, but you won't blow up the capacitors.
PowerPlay III PDA: 2MB Flash, 8MB RAM, No MMU $89.99
Agenda VR3: 16MB Flash, 8MB RAM, MMU $249.00
Agenda has an active developer community, so the software is actively getting better pretty quickly. Does the PowerPlay have any developer program?
I want more RAM and/or flash for my Agenda, the PowerPlay has much less. So the PowerPlay III isn't going to fill the same niche as my Agenda.
But the PowerPlay website says the Flash is expandable, but gives no details.
I'd like a durable, small, low power embeddable Linux device with a display. Can you connect the PowerPlay to your network and also use some other I/O ports? The Agenda is pretty I/O limited, it also doesn't have a spot for external power (cut a dowel into fake AAA batteries...).
If you're going to solder, get one of those little DC/DC convertors in a black epoxy brick that makes -5V from +5V or +12V.
If you're really cheap, some old ethernet cards have isolated 5V to 9V convertors in them. Use one of them and a 7805 to get an isolated 5volts. Tie the isolated +5V to system ground, and the ground from the 5volt supply will be at -5V.
Lego's apparent need to
make 200x the custom, one use only, decorative pieces?
Try playing with them like a six year old.
My six year old son spends a lot of time adding special equipment onto robots, planes, spaceships, cars, submarines, etc... An arm from a Bionicle makes a fine rocket engine. Did you know that if you put a propellor onto car, it can be a submarine, too?
Try connecting the "decorative pieces" in different ways. Notice how Lego uses just a few basic dimensions again and again. A Lego axle fits in the same size hole as a bump on the basic brick, as does the tip of the Lego pine tree and a gazillion other Lego parts. Likewise, many things are just the right size for a minifig's hands (claws).
If the instructions in the fancy sets blind you to the other ways to use the pieces, just buy the big blue tubs of basic bricks.
Oops, my bad. I read the page www.mosys.com/discrete.html
too fast. The biggest part listed there is 9 Mbytes, not 9Mbits. Also, the page says Last Updated on 12/11/00 .
Some percentage of system clocks are just set wrong. I sorted my email by date, the message with the worst time warp was dated Sun, 24 Jan 2094 14:55:27 +0100.
These people with flaky hardware and/or flaky administrators are providing a valuable service and testing bunches of applications for us. This does provide uneven coverage, applications for the clueless get the most wrong date testing. The headers say that message from 2094 was sent with Microsoft Outlook Express 5.50.4133.2400.
Some [gift giving] relatives don't understand why you might want two identical kits, so Lego should market "The RIS 2.0 IO Expansion kit" which would be a normal RIS 2.0, but with a sticker on it that says "IO Expansion kit".
It isn't hard to network RCX's so you have more than 3 inputs and outputs. Or rather, it isn't hard with LegOS or NQC.
If Lego provided an example client server applications, it wouldn't be so intimidating. Lot's more people would buy two sets.
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If they're new CDwriters, they'll have protection against making coasters, so the penalty for running too many CDwriters, is they'll slow down.
If you're good with metal working tools, you can make a double wide case that can hold 10 drives. Plug a bunch of IDE controller cards into the PCI bus. Note: IDE cables are limited to 18 inches. So you have to do a little design work, before you start cutting metal.
If you're not into metal working, just take a few cheap PC's, max them out with CDwriters and network them with 100base-T ethernet cards. A little glue, and it will be like one big machine. This design can be expanded to hundreds of drives.
I'm assuming student labor, so you won't need a robot disk changer.
Seems accurate to me. Amazon choses to use low margins only where there is competition, and then only if they want to "win" in that marketplace.
The high price ebook business model isn't on a firm foundation, so there's little business reason to try and capture that market.
Ebooks will take off when the books get much cheaper, and the authors get to keep most of the "cover" price. Textbook authors often get less than 10% of the cover price on paper books.
Imagine if the author got $4 royalty and the editor got $1 on a $6 e-textbook, they'd both make more money per book, and the students would spend less per book. The intellectual property creators and consumers would win, and the middlemen, the publishers, printers, and distributors would need to find new jobs.
Alas, the publishers have lots of lawyers and are delaying this as long as they can.
That means device development. Software development is being done by the user community.
Agenda Germany should concentrate on hardware, since that's not something that we can do by ourselves very well. I'd rather buy a mass produced Agenda with 16MBytes of RAM, rather than spend hours soldering.
That's true for Cable TV, so Cable TV cables are already relatively clean.
This is probably one of the reasons they are focusing on cable TV. Most other existing wired technologies (phone, ethernet, speaker wires, etc...) tolerate reflections much better, so the infrastructure has a lot more of them.
It would be worth $20 to $30 to not need to get out the dremel and make my own rear facing drive bay.
The other choice is externally mounting the CD-Writer. That makes the whole system more fragile. More of a pain to move and to work on. It's hard to run IDE cables externally, possible, but hard. SCSI CDWriters are either slower, more expensive or both. USB 1.1 is slower. Firewire and USB 2.0 are more expensive. Check pricewatch.com, $71 for 24x10x40x IDE, USB 1.1 is limited to 4X4X6X ($85), firewire starts at $144.
As we all know, VCRs helped most of the movie companies prosper. Now look at the executives. Video sales and rentals helped a bunch of executives climb the movie company corporate ladders. Which means turnover at the top.
The folks choosing to bring the lawsuits, might be afraid that their company will suffer, or more likely, they're afraid that they personally will suffer.
Naturally, such systems get enhanced so they can send more data at the cost of a little harmonic purity. For expample, they could get 50% more data through by using pairs of trits to send 3 binary bits. The 9th state would be used to prevent leaving the line at one voltage level too long. The real encodings are better behaved in the analog domain, and therefore more complex, but lookup tables for the trit to binary conversions take very little silicon.
For those who haven't memorized powers of three, if trinary logic, memory or signalling works better in some situation, 1 trit holds 1 bit, 2 trits hold 3 bits, 12 trits hold 19 bits, 31 trits hold 49 bits, etc...
Going the reverse is also very simple. If you have an algorithm that works better in trinary, store 1 trit in 2 bits, 3 trits in 5 bits, 5 trits in 8 bits, etc... You don't need special hardware.
It's a lot cheaper to make many different sized tanks than to make many different sized batteries.
Maximum tank size will probably be limited by safety concerns.
RADIUS is just an authentication protocol, it doesn't provide privacy. Sript kiddies will have to pretend to be using systems that have active sessions. Ok, the script kiddie may not know what's going on, their scripts will have to pretend.
RADIUS may work, but you've still got to replace WEP.
Ignore WEP and use real security on your link. There are many options.
All the Unix backup tools can backup to disk as easily as to tape. Carriers to make ATA/100 disks removable cost about $10 each. ATA/100 disks are cheap per megabyte.
There are techniques to make the disks hot swappable, or use a dedicated backup machine that can be easily powered down to swap disks.
Most importantly! It's a restore system, not a backup system.
Nobody cares how great your backups are, if you can't do a restore when you need it.
I played with it for a while many months ago. After reading this Oreilly Net Article about it. The link is to page 2, because that's where the calibration stuff is.
This is how you can find out where all the pixels are pointing. I suspect there is code for calibrating intensities, but I didn't use it.
For added annoyance value, use random data instead of zeros.
You'll still want to armor the cable, put in a bunch of dummy fibers and many of the other things that were suggested.
Hydrogen + oxygen burns to make pure water over a wide range of temperature and pressure. Dilute the oxygen and it takes more pressure. At some combinations of temperature and pressure, it'll also combine some oxygen with nitrogen and make stuff that isn't so clean.
At best, it's decades away from something practical for a car.
With a cable modem, the only difference is that the very first hop might also be oversubscribed.
A cable has a lot of bandwidth. That bandwidth is divided up into channels (on an NTSC analog system, channels are all 6Mhz wide, your channels may vary). Each internet cable box is assigned a channel (or set of channels, if channels only come in one size). Your next door neighbor's cable box might use a different channel, and thus not be in the same neighborhood.
Logically, a cable system is a tree, or set of trees, with the root of each tree at the cable company office, and the customers are the leaves. The thicker branches may run on fiber, they support more channels, and therefore more neighborhoods.
A wee tiny cable company may have a single T1 (1.5Mbps) line connecting to the greater internet, a large company might have several OC48 (2.5Gbps). The same is true for DSL providers.
ISP's either charge premium rates or they oversubscribe the service, or both. I don't see a primetime slowdown on my $180/month, 384K DSL line.
Many motherboards only support a single 33 Mhz/32 bit(4 byte) PCI bus, that is only 133Mbytes/second. With 3 or more new fast ATA/100 drives (limit 1 per cable) and cheap IDE controllers, you can run out of PCI bus bandwidth.
Under the heading 3ware?, cymen listed some IDE RAID controllers that will work in a 66Mhz/64 bit PCI bus. The motherboards cost more, but the speed limit is 528Mbytes/second.
We use software RAID with IDE, because the main processor is 1.4Ghz or better and has access to 1 or 2 gigabytes of buffer memory. If you are CPU limited, it is much cheaper to get a dual CPU motherboard, than to get a fast hardware RAID system.
It's not just a hardware issue. Which OS or OS's do you want to support? A solution that works for Linux may not work on some flavor of BSD. You might even be stuck with one of the dozens of lesser OSs.
Capacitors blow up from too much heat, which for a DC power supply filtering capacitor implies too much voltage. Capacitors are in parallel with the power supply. Something put too high a voltage across the capacitors.
Unless I'm really confused, the highest voltage on the IDE connector is only 5 volts, and all of the pins on the IDE connector are either ground or are compatible with 5 volts. You can hurt the logic chips and the power supply by shorting stuff on the IDE connector, but you won't blow up the capacitors.
Agenda VR3: 16MB Flash, 8MB RAM, MMU $249.00
Agenda has an active developer community, so the software is actively getting better pretty quickly. Does the PowerPlay have any developer program?
I want more RAM and/or flash for my Agenda, the PowerPlay has much less. So the PowerPlay III isn't going to fill the same niche as my Agenda. But the PowerPlay website says the Flash is expandable, but gives no details.
I'd like a durable, small, low power embeddable Linux device with a display. Can you connect the PowerPlay to your network and also use some other I/O ports? The Agenda is pretty I/O limited, it also doesn't have a spot for external power (cut a dowel into fake AAA batteries ...).
If you're really cheap, some old ethernet cards have isolated 5V to 9V convertors in them. Use one of them and a 7805 to get an isolated 5volts. Tie the isolated +5V to system ground, and the ground from the 5volt supply will be at -5V.
Try playing with them like a six year old.
My six year old son spends a lot of time adding special equipment onto robots, planes, spaceships, cars, submarines, etc... An arm from a Bionicle makes a fine rocket engine. Did you know that if you put a propellor onto car, it can be a submarine, too?
Try connecting the "decorative pieces" in different ways. Notice how Lego uses just a few basic dimensions again and again. A Lego axle fits in the same size hole as a bump on the basic brick, as does the tip of the Lego pine tree and a gazillion other Lego parts. Likewise, many things are just the right size for a minifig's hands (claws).
If the instructions in the fancy sets blind you to the other ways to use the pieces, just buy the big blue tubs of basic bricks.
Oops, my bad. I read the page www.mosys.com/discrete.html too fast. The biggest part listed there is 9 Mbytes, not 9Mbits. Also, the page says Last Updated on 12/11/00 .
Static RAM has faster access times than DDR-SDRAM, so it is appropriate for some uses.
I don't know how this technology compares with other static RAM technologies.
These people with flaky hardware and/or flaky administrators are providing a valuable service and testing bunches of applications for us. This does provide uneven coverage, applications for the clueless get the most wrong date testing. The headers say that message from 2094 was sent with Microsoft Outlook Express 5.50.4133.2400.
It isn't hard to network RCX's so you have more than 3 inputs and outputs. Or rather, it isn't hard with LegOS or NQC.
If Lego provided an example client server applications, it wouldn't be so intimidating. Lot's more people would buy two sets.