brainwagon

A few years ago, Tom Duff and I each wrote an emulator for the PDP-1 so we could play the original version of Space Wars! I learned a lot about old computers in the week or so it took me to do, and I must admit that I’ve retained a fascination for old computers ever since. Tom mentioned that he has a front panel from an old PDP-11, and has talked about doing a project where he wires the front panel to a more modern machine running a PDP-11 emulator, which seemed like a cool idea. After all, modern computers just don’t have enough blinking lights. Here’s a link to a project which does precisely that using an inexpensive Zilog microcontroller over ethenet. It also includes some links to other similar and interesting projects. Check it out.

Re-animating the PDP-11/70

Here’s a way to turn an ATMEGA168 into an Arduino compatible controller with a minimum of external components.

arduino-standalone « Conversations with spaces

This is just completely nuts, an 8 bit computer constructed entirely from 12 volt relays. It consumes 12 amps at 13.5 volts (160 watts). Hilarious.

[tags]Retrocomputing,Hacks[/tags]

Well, Steve is still up there, but the big news (as yet unreflected on the Apple website) is the announcement of a new Intel based iMac. It will apparently come in the same sizes and prices as previous G5 iMacs, but will use Intel’s new CoreDuo processor that was plugged by Intel so heavily at CES last week.

There is also some nice improvements to their existing iLife suite, including the addition of the (somewhat predictably name) iWeb: a web authoring suite that includes the ability to create and publish rich media websites using premade Apple templates. Notable for podcasters, GarageBand will also include a Podcast Suite: a set of features designed to make the creation of podcasts simple and easy.

Addendum: Two new laptop models will be available in February: the MacBook Pro, also with the Core Duo Processor, $1999 and $2499.  It will include the iSight camera, Front Row, all that kind of stuff.  Neat!

[tags]Apple,Podcasting,MacWorld,iMac,Intel[/tags]

Check out this video on Google showing an overclocked AMD Duron vaporizing. They clocked it up in both frequency (3.8ghz) and I believe also significantly over voltage, but still, pretty amazing. They just didn’t let the magic smoke out, they literally destroyed the chip.

The most daunting challenge facing computing isn’t speeding up computers, it’s controlling heat. Cool stuff.

Linksys has sold a bazillion of the old WRT54GS routers. It’s probably due in some small part to the many alternative firmware upgrades you can put on the device to increase its capabilities in a number of innovative directions. The most recent versions of these devices are somewhat less hackable though. The series 5 devices have shifted from using Linux to using VxWorks, and have cut memory down to 2MB of Flash and 8MB of RAM, instead of 4MB of flash and 16MB of RAM for earlier Linux based devices. But to placate the hacker market, Linksys has released the WRT54G”L” which retains the larger memory spaces of earlier models. How long will it last? Hard to say, I’ll be watching this experiment to see how it goes.

This dive into the world of retro computing has rekindled my interest in field programmable gate array technologies. I found this page which contains interesting FPGA based CPU designs. Mostly marked as a bookmark to re-examine later.

Dave went out and bought himself a couple of those single use, $25 camcorders that CVS is selling these days, and hacked them to allow download of video. What is even better, he snapped video of the project and made it available for download.

Caveat: it appears to be encoded in some kind of Quicktime 7 specific codec. I haven’t bothered to get Quicktime 7 on my laptop, since it is beta still for Windows, but I did notice that it will play nice using VLC. Hooray for VLC!

Broadband Reports has this cool overview of where residential networking is likely to go in the next few years. I’m currently stuck on cable modem because we are too far from the phone switch for DSL, but it is good to see what might be possible in the next few years.

Here is an interesting early paper on the justification, implementation, analysis and use of random number generators, written in 1959. The resulting machine generated about 5000 bits per second, not bad!

Via Boing Boing. By the way, random numbers are still cool.

Real World Technologies lists an interesting article about the AMD K8 processor and its previously unnoticed ability to patch its own microcode. Apparently AMD has used this to repair a couple of bugs in the processor in the past, but nobody really noticed it before.

A couple of quotes from the article:

The ability to fundamentally alter instruction decoding and execution on AMD K8 processors is sure to interest hardware hackers everywhere.

…

For instance, by patching the appropriate microcode lines, it may be possible to catch an opcode that would normally be illegal, and instead handle it by tricking the TLB into thinking we’re in kernel mode when in fact the attacker has only compromised a userspace process. From there, the attacker could control the entire machine, all without altering a single bit of “software”.

That sounds scary. But wait: there is more!

There may also be a hidden danger to altering K8 microcode without complete information. It is possible (though very unlikely) that the microcode could electrically reconfigure signal routing in a fashion similar to FPGAs, for instance to cut off defective logic and reroute signals to redundant arrays. This approach has been used in the past and the AMD patents even suggest it.

If this were the case, there is a very remote chance the CPU itself could be permanently damaged, for instance, by tri-stating pass transistors into a high current draw state or adjusting the K8’s voltage and frequency scaling controls out of spec. This is not meant to discourage potential hackers; I have just seen programmable logic literally destroyed by buggy “software” bitstreams.

Gee, that doesn’t sound very good.