This page is mostly here for my reference, and to vent as I couldn't find this information anywhere else (ie google).

US Robotics Modem Power Supply

I had two USR modems in a bag without realising that their power adapters were different voltages, and which went with which is not documented anywhere. So for the benefit of anyone who needs to know, the 20 volt pack works with the 33.6K Sportster Voice modem and the 9 volt pack works with the 56K Voice modem. Disclaimer: if I have got this wrong, and this causes you to burn down your house, it's not my fault.

Genius Ethernet PC-Card

Genius MF3000II CardBus 100/10 Mbit ethernet card - this is a removable PC-card that uses a Realtek 8139 chip. The pcmcia-cs package with Debian 3.0 (Woody) wants to use the tulip driver that is not only hopelessly outdated but is known to be incredibly buggy on some cards (v0.91g I think the driver identifies as). Not useful AT ALL when you are trying to install Debian with a boot cd and expecting to use your network link to complete the install. The 2.4 kernel's 8139too driver works mostly, but craps out at high utilisation. My solution was to download Donald Becker's 8139 drivers from http://www.scyld.com/network/rtl8139.html which have been fine so far.

Sound crashes your Acer Travel Mate laptop?

In /usr/src/linux/drivers/pci/quirks.c, (Line 488 in 2.4.19) you'll see a bunch of lines that look like this

{ PCI_FIXUP_FINAL, PCI_VENDOR_ID_??, PCI_DEVICE_ID_????????, quirk_isa_dma_hangs }

After all those, add

{ PCI_FIXUP_FINAL, PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, quirk_isa_dma_hangs }

Problem solved.

MVP3 (super socket 7, K6-2) chipset motherboards

Some motherboards using this older chipset have small L2 caches, meaning if you have too much RAM then performance will become very slow when it is in use. The boards with 512KB can only cache 128MB, and the boards with 1MB can only cache 256MB, so if you are using ram above that limit then all memory reads/writes will take a lot longer.

Theres reference for mother boards that do this that you can turn the uncached memory into very high speed swap space. This means that as long as your working set is inside your cachable memory then your computer is very very fast. Anyone know if you can convince Linux to use swap in preference to disk I/O? (ie: swap out disk cache onto a faster medium such as this 'high' memory?) -- PerryLorier

Power Supply

If you want to blow up your power supply unit, simply forget to plug the connector into your motherboard after changing it, then plug the power into the wall. (This was a 230W Hyena brand PSU by the way). Update - it appears a capacitor blew its cover right off. See pretty picture Update2: it appeared to have damaged the IDE HDD as well! Moral of the story - don't buy Hyena brand power supplies.

Most External Serial Dynalink Modems (Older models i.e. >= 33.6k)

These may use AC? (as opposed to DC?) power supplies - some other devices don't like this :)

Monitor Burn-in

Old CRT monitors and early plasma screens used to suffer from burn-in; if the same image was displayed on the screen for a long time it would eventually become permanently burned into the phospor. Screensavers were invented so that the monitor would have a constantly changing image to display and thus be 'saved' from burn in. On newer CRT monitors and LCD displays burn-in is not a factor.

[The emac pictured below is switched OFF. the clearly visible message you see on the screen is burn-in]