Date: Sun, 15 Dec 1996 22:13:53 +1100 From: Bruce Evans <bde@zeta.org.au> To: freebsd-hackers@FreeBSD.org, j@uriah.heep.sax.de Cc: tony@dell.com Subject: Re: MAXMEM was: Re: 2.1.6 on Compaq Prosignia 500 (2.1.5 worked) Message-ID: <199612151113.WAA01612@godzilla.zeta.org.au>
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>What BIOS calls? My old notebook is probably the oldest machine that >somebody would be willing and able to run FreeBSD on (386/16, 5 MB >RAM, approx. 1990/91), so i could test its BIOS for the existance of >that call. You don't have >= 64MB extended memory, so the existence of the calls doesn't matter. What matters is that they fail correctly if they are not supported. The Interrupt List version 46 (June 1995) gives the at least the following calls: --- INT 15h/AH=88h The standard call, used in our boot blocks. Limited to 64MB. Said to be unreliable because some BIOSes don't set the carry flag if they don't support it. INT 15h/AX=DA88h. Works on AMI PCI BIOS. Returns size in K in CL:BX. INT 15h/AX=E801h. Works on some Compaqs and Dells. Details not all known. Limited to 64M. INT 15h/AX=E802h. Works on some Compaqs. Details not known. INT 15h/AX=E802h. Works on some Dells. More details given than for Compaq, but not enough to actually use it. It can apparently report any number of discontiguous regions. --- There is probably a standard way now, but it may not work on the old Compaqs and Dells. Some have a stupid 15 or 16MB limit, so they hit the limit a couple of years before other systems. Bruce
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