Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site psivax.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!houxm!vax135!cornell!uw-beaver!tektronix!decvax!ittvax!dcdwest!sdcsvax!sdcrdcf!psivax!al From: al@psivax.UUCP (Al Schwartz) Newsgroups: net.micro.pc Subject: Re: Dos Startup modification Message-ID: <307@psivax.UUCP> Date: Mon, 4-Feb-85 21:18:38 EST Article-I.D.: psivax.307 Posted: Mon Feb 4 21:18:38 1985 Date-Received: Sat, 9-Feb-85 04:53:43 EST References: <11841@gatech.UUCP> Reply-To: al@psivax.UUCP (Al Schwartz) Distribution: net Organization: Pacesetter Systems Inc., Sylmar, CA Lines: 33 Summary: In article <11841@gatech.UUCP> klute@gatech.UUCP (Gregory Kenley) writes: >A while back I remember reading an article in either PC or PC-Tech regarding >modifying DOS on startup to skip the memory test. >Gregory Kenley >CSNet: klute @ GATech ARPA: klute%GATech.CSNet @ CSNet-Relay.ARPA >uucp: ...!{akgua,allegra,hplabs,ihnp4,linus,seismo,ulysses}!gatech!klute The memory test code for the IBM is contained in the ROMS that are plugged into the motherboard of the machine. The memory has to be tested first before the DOS can be booted in. Therefore to make this change in software one must make new ROMS (very expensive). One way I can think of doing this though, is to set your memory size switches on the motherboard for a lesser memory size (so that only that amount will be tested by the ROM code) and then later change the memory location(s) that the DOS (or BIOS) uses to keep track of the memory size. That way the programs that you run will know how much memory. You will also have to run a program that ignores parity errors and then reads each location of memory that was not tested in order to set the parity bit correctly, otherwise you'll get a parity error when you attempt to use the memory. This will only work with DOS versions less than 2.0. In DOS 2.0 they added a memory management scheme that allocates memory when booted to correspond to the switch settings. Any attempt to allocate more than the switch settings were set to will cause the memory allocate algorithm to fail. My IBM PC takes 51 seconds to test the RAM (640K). Thats just enough time to go out an get a beer and pretzels. -- Yow! Am I having fun yet? Al Schwartz Pacesetter Systems Inc., Sylmar, CA {trwrb|allegra|burdvax|cbosgd|hplabs|ihnp4|sdcsvax|aero|uscvax|ucla-cs| bmcg|sdccsu3|csun|orstcs|akgua|randvax}!sdcrdcf!psivax!al