hadeishi@husc7.HARVARD.EDU (Mitsuharu Hadeishi) (04/27/87)
Yes, and there was also a location on some of the older versions of the PET microcomputer (remember them?) way back when which, if you POKEd a particular location, would destroy your computer. Honest. It was some kind of hardware control register if, when given the wrong value, would smoke your machine. Any other tales? :-) -Mitsu
woodside@ttidca.UUCP (04/29/87)
The old Compucolor II computer from ISC was very vulnerable to certain hardware tinkering. This was an 8080 machine, with 48K of RAM, and 16K of ROM/hardware registers. Tampering with the addresses that accessed the hardware registers could wipe out all the RAM (it did something fatal to the refresh logic). It used an Intel CRT controller for screen processing. Altering the number of scanlines to too high a value could kill the CRT. The ROM contained a ripped-off version of Microsoft BASIC and a simplistic file system. Microsoft found out about them, and forced ISC to become a Microsoft distributor. They also collected royalties on all machines sold up to that time. The real comedy of this box was the disk drive. The thing was originally designed to use an 8-track tape cartridge for storage (yes, you read that right!). When that proved to unreliable, they switched to a 5.25 inch disk dirve. They didn't change the file system, which still thought it was a tape drive. When you deleted a file, it re-packed all remaining files back to the front of the disk. Used the 8K of screen RAM for a buffer to do it, which led to some psychedelic I/O.
kevin@Lindy.UUCP (05/08/87)
The talk about the ISC computer reminds me of the Apple Silentype printer. I got very strong warnings against trying to access the printer directly through the Apple II's memory-mapped I/O; apparently you could make the printer (literally) blow up. God, I hated that printer.