dbullis@cognos.UUCP (Dave Bullis) (05/28/90)
In article <8343@cognos.UUCP> dbullis@cognos.UUCP (Dave Bullis) writes: >I was told by one the local clone dealers that there are problems >with mixing 80386 25MHz cache systems and VGA cards. > ... I talked to the dealer again for more details: He says that some 8-bit VGA cards caused the system to hang when booting. 16-bit cards are ok. -- Dave Bullis Cognos, Inc VOICE: (613) 738-1440 3755 Riverside Dr. P.O. Box 9707 FAX: (613) 738-0002 Ottawa, Ontario, CANADA K1G 3Z4 UUCP: uunet!mitel!sce!cognos!dbullis "I didn't know the terminals were haunted. The salesman didn't tell us."
campbell@Thalatta.COM (Bill Campbell) (05/31/90)
In article <8415@cognos.UUCP> dbullis@cognos.UUCP (Dave Bullis) writes: :>In article <8343@cognos.UUCP> dbullis@cognos.UUCP (Dave Bullis) writes: :>>I was told by one the local clone dealers that there are problems :>>with mixing 80386 25MHz cache systems and VGA cards. :>> ... :> :>I talked to the dealer again for more details: He says that some 8-bit :>VGA cards caused the system to hang when booting. 16-bit cards are ok. :> I had exactly the opposite problem with a 33Mhz NIC Motherboard, 32K cache. It wouldn't writefloppy disks properly when using a 16-bit Paradise board, but running with the board in an 8-bit slot or substituting an 8-bit board cured the problem. This problem has also been reported on the HP-Vectra. The article on the Vectra implied that the problem was with any O/S running in the 386 protected mode. -- ....microsoft--\ Bill Campbell; Celestial Software ...uw-entropy----!thebes!camco!bill 6641 East Mercer Way ....fluke------/ Mercer Island, Wa 98040 ....hplsla----/ (206) 232-4164
martin@hppcmart.HP.COM (Martin Croome) (05/31/90)
>campbell@Thalatta.COM (Bill Campbell) writes: >In article <8415@cognos.UUCP> dbullis@cognos.UUCP (Dave Bullis) writes: >:>In article <8343@cognos.UUCP> dbullis@cognos.UUCP (Dave Bullis) writes: >:>>I was told by one the local clone dealers that there are problems >:>>with mixing 80386 25MHz cache systems and VGA cards. >:>> ... >:> >:>I talked to the dealer again for more details: He says that some 8-bit >:>VGA cards caused the system to hang when booting. 16-bit cards are ok. >:> >I had exactly the opposite problem with a 33Mhz NIC Motherboard, >32K cache. It wouldn't writefloppy disks properly when using a >16-bit Paradise board, but running with the board in an 8-bit >slot or substituting an 8-bit board cured the problem. This >problem has also been reported on the HP-Vectra. The article on >the Vectra implied that the problem was with any O/S running in >the 386 protected mode. > The problem is that with the Paradise card in 16bit mode the video RAM is not fully decoded so the card will appear in each 1Mb block of the PC's memory space. The cache should not be enabled over the VGA card's RAM. If it was it would cause problems with the card. Most PC's disable the cache on writes and reads to and from memory at addresses between 0xA0000 and 0xDFFFF to avoid this problem. >-- >....microsoft--\ Bill Campbell; Celestial Software >...uw-entropy----!thebes!camco!bill 6641 East Mercer Way >....fluke------/ Mercer Island, Wa 98040 >....hplsla----/ (206) 232-4164 >---------- ------------------------------------------------------------------------------- Martin CROOME !'s - hplabs!hpgnd!hppcmart!martin Hewlett Packard @'s - martin@hppcmart.grenoble.hp.com Grenoble Personal Computer Division HPDesk - Martin CROOME / HP6300/K1 Technical Mktg - Online Support -------------------------------------------------------------------------------
wtm@uhura.neoucom.EDU (Bill Mayhew) (06/02/90)
I know from experience that AT&T (about the same as ISC) Unix will not boot unless you have a 16 bit VGA controller and that controller is in a 16 bit slot. It'll boot from an MDA card too, of course. Cruiously, AT&T's 6386 hardware service guide shows the VGA card installed in an 8 bit slot. One of our staff people received a 6386 that had been configured by AT&T. Apparently, they must have followed the service guide. It would boot DOS, but when he tried to install the Unix bundle that came with the machine it would gag. He called, and I switched the card to a 16 bit slot, and all was fine. I can't really think of any reason why a VGA card would have problems with a cache system. I am running AT&T 3.2.1 on a JDR 33 MHz MCT board with a 64K cache and an OEM verison of the Paradise VGA Plus/16. No problems. Unix does not use the DOS BIOS for anything except to read the first level bootstrap loader from the hard drive. The reason is that DOS BIOSES use software interrupts for virtually everything. INTs aren't available in protected mode, so the results would be a real mess. The DOS BIOS also in not at all reentrant, so the kernel couldn't use the BIOS anyway. IBM is an exception. The model 80 (which the only one I have personal experience with) has a second BIOS, called, 'ABIOS' which is accessible from protected mode (A for advanced). The regular BIOS is called, 'CBIOS' (C for compatibility). The ABIOS works by calling the functions via long jumps sort of a-la CP/M, if any of you old-timers remeber that. Perhaps Xenix for PS/2s uses the ABIOS; that wouldn't surprise me too much given my experiences with SCO :-). == Bill == -- Bill Mayhew Northeastern Ohio Universities College of Medicine Rootstown, OH 44272-9995 USA 216-325-2511 wtm@uhura.neoucom.edu ....!uunet!aablue!neoucom!wtm