Zuse Z1/Z3 The
Z1 (1938) and
Z3 (1941) computers built by
Konrad Zuse contained illegal sequences of instructions which damaged the hardware if executed by accident.) made the machine able to display text and graphics on the screen 106% faster. This was accomplished by disabling a "wait to print to screen" safeguard designed to reduce static/noise by preventing the shared
VRAM from being read by the display at the same time as it was being written to by the CPU. With this safeguard disabled, graphics could appear on the screen twice as fast, but small bits of static would also appear. Despite the static, some games designed for early PETs included this POKE in their source code in order to benefit from the faster graphics. This is because the exact pin targeted by the POKE command used to control display timing, but in the upgraded video chip, that pin controlled the vertical sync. Thus, running the POKE on the newer hardware caused graphics to compress vertically, sometimes down to an extremely bright horizontal line. Fears that this anomaly might
burn in to the display led to the nickname "killer poke";
Commodore 1541 Disk Drive The
Commodore 64 had an optional external 5-1/4" floppy drive. The
Commodore 1541 contained a 6502 microprocessor which was used to run
Commodore DOS and also to manage the drive mechanism. The drives stored data on 35 tracks (#0–34), and the stepper motor could be manually controlled through BASIC by PRINT#-ing "MEMORY-WRITE" commands to the drive (which correspond to the POKE command of BASIC, but write to the drive's internal memory and I/O registers, not those of the computer itself). If the drive was at either end of its range (track 0 or track 39) and it was commanded to continue moving, there was no software or firmware method to prevent drive damage. Continued "knocking" of the drive head against the stop would throw the mechanism out of alignment. The problem was exacerbated by
copy protection techniques that used non-standard disk formats with unusual track counts. The
Commodore 1571 had an optical head stop instead of a mechanical one.
LG CD-ROM drives Certain models of LG CD-ROM drives with specific firmware used an abnormal command for "update firmware": the "clear buffer" command usually used on CD-RW drives. Linux uses this command to tell the difference between CD-ROM and CD-RW drives. Most CD-ROM drives dependably return an error for the unsupported CD-RW command, but the faulty drives interpreted it as "update firmware", causing them to stop working (or, in casual parlance, to be "
bricked").
Flash memory The resource of flash memory is large, but limited. Since writing to storage is an essential operation, most applications have enough privileges to exhaust the resource of flash chips within 24 hours by filling the storage enough to cause
write amplification and continuously rewriting a small file.
MSi Laptops UEFI Systemd mounts variables used by
Unified Extensible Firmware Interface on
Linux system's
sysfs as writable by the root user of a system. As a result, it is possible for the
root user of a system to completely brick a system with a non-conforming UEFI implementation (specifically some
MSi laptops) by using the rm command to delete the /sys/firmware/efi/efivars/ directory, or recursively delete the
root directory. ==See also==