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Revision as of 08:34, 25 December 2023 edit Guy Harris (talk \| contribs) Extended confirmed users 74,530 edits →‎Writable stores: Ask for a citation on WCS making it harder to debug programs. Copyedit. ← Previous edit		Latest revision as of 11:00, 25 December 2023 edit undo Michaelmalak (talk \| contribs) Extended confirmed users 2,276 edits Undid revision 1191719403 by Guy Harris (talk) Revert cn and added quote to already-existing cite to make clear
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Line 48: The [[Data General Eclipse MV/8000]] ("Eagle") has a SRAM writable control store, loaded on power-on through another CPU.<ref>{{cite web\|author=Mark Smotherman\|title=CPSC 330 / The Soul of a New Machine\|url=http://www.cs.clemson.edu/~mark/330/eagle.html\|quote=4096 x 75-bit SRAM writeable control store: 74-bit microinstruction with 1 parity bit (18 fields)}}</ref> WCS offers several advantages including the ease of patching the microprogram and, for certain hardware generations, faster access than ROMs could provide. User-programmable WCS allow the user to optimize the machine for specific purposes. However, it also ~~has~~had the ~~disadvantages~~disadvantage of making it harder to debug programs~~{{cn}}~~, and making it possible for malicious users to negatively affect the system and data.<ref>{{cite journal \|last=McDowell \|first=Charlie \|date=1982 \|title=Protection at the micromachine level \|url=https://dl.acm.org/doi/pdf/10.1145/859520.859521 \|journal=ACM SIGARCH Computer Architecture News \|volume=10 \|issue=1 \|pages=5 \|doi=10.1145/859520.859521 \|access-date=2023-11-25 \|quote=It is not unusual to find microprograms that are greater than 50K bytes in size. This increase in size, and the expansion of microprograming beyond the traditional bounds of machine instruction emulation, have increased the possibility of both malicious and faulty microprograms, particularly the later.}}</ref> Some CPU designs compile the instruction set to a writable [[RAM]] or [[Flash memory\|FLASH]] inside the CPU (such as the [[Rekursiv]] processor and the [[Imsys]] [[Cjip]]),<ref>{{cite web\|url=http://cpushack.com/CPU/cpu7.html \|title=Great Microprocessors of the Past and Present (V 13.4.0) \|publisher=Cpushack.com \|access-date=2010-04-26}}</ref> or an FPGA ([[reconfigurable computing]]).