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Another reason to not copy what the west was doing was the deliberate crippling of early systems. It's difficult to find this information on the web, but I rec
by anonymousiam 6y ago
Another reason to not copy what the west was doing was the deliberate crippling of early systems. It's difficult to find this information on the web, but I recall that the early IBM PC/AT machines ran at 6MHz and contained BIOS code that prevented them from booting if they were clocked any faster. (Later versions ran at 8MHz.)
The reason was to prevent people from buying IBM PC/AT machines instead of IBM RISC 6000 workstations.
- jecel 6y agoI think early 286 chips didn't go up to 8MHz. The IBM RT PC (the ancestor of the 6000) was only introduced 2 years after the AT: https://en.wikipedia.org/wiki/IBM_RT_PC https://en.wikipedia.org/wiki/IBM_RT_PC
- chipotle_coyote 6y agoHmm. The Tandy 2000, Radio Shack's ill-fated first foray into the world of MS-DOS in 1983, used an 80186 (yes, 186) clocked at 8 MHz, so it would seem odd if the 80286 couldn't have at least matched that. From what I can find at a cursory search, the 80286 first shipped at 5 MHz, 6 MHz and 8 MHz versions, although the AT apparently used the 6 MHz version when it first shipped in 1984, not bumping up to 8 MHz until 1986.
- hakfoo 6y agoWhile there was plenty of overspec in the AT design, it was built around a CPU rated by the vendor for 6MHz operation. You don't want the support headaches when some local reseller cracks the case, swaps in faster crystal, and things mostly work. There were aftermarket speedup circuits which you could turn on after the POST check completed; I recall one with a knob offering like 8 different speeds.
- hadlock 6y agoI always wondered why my friend's dad's computer had a TURBO button on it, thanks!