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Atari PC5 bios from http://www.ataripc.net/biosrom-images/

If I try to load it in at.cpp as an at386 with

Code:
ROM_START( ataripc5 )
	ROM_REGION(0x20000,"bios", 0)
	ROMX_LOAD( "ami_pc5_1.00_rom0.bin", 0x00000, 0x8000, CRC(496149a6) SHA1(81033b22af830af8306abfde03a194739fe54355), ROM_SKIP(3))
	ROMX_LOAD( "ami_pc5_1.00_rom1.bin", 0x00001, 0x8000, CRC(3c82fe66) SHA1(dd6c2c3c3635761b1d928912269b8937cbdc09ae), ROM_SKIP(3))
	ROMX_LOAD( "ami_pc5_1.00_rom2.bin", 0x00002, 0x8000, CRC(7dc5b53b) SHA1(33e138baa84a8acc629bde5a6b54e47d0d4508f1), ROM_SKIP(3))
	ROMX_LOAD( "ami_pc5_1.00_rom3.bin", 0x00003, 0x8000, CRC(b588b7a8) SHA1(2f2597b14e54d03cf957cce47536266f68d3aa66), ROM_SKIP(3))
ROM_END


all I get is continuous beeps - not even AMI beep codes.

At the beginning of the BIOS is an AMI EGA BIOS, probably with the same functionality as described here in an old PC magazine:

Quote:
This BIOS uses 128K more ROM than many other BIOS chips on the market. The extra ROM is used to house setup, diagnostics, and an EGA BIOS. The on-board EGA BIOS, which can be enabled through a switch, can be used in place of an EGA board, so that monitor instructions do not have to be carried over the slower bus. This results in much faster video speeds without RAM shadowing. If you have a VGA monitor-and-card combination, however, only the EGA functions will be speeded up.


I'm probably not loading the BIOS to its proper place due to the presence of the additional EGA BIOS.


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
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After some Googling, I found http://www.atari-computermuseum.de/pics/scans/pc5.pdf

Page 30 says
Code:
	ON-BOARD EGA BIOS OPTION
	----------------------------------
SW1	ON/OFF	EPROM MAP	DESCRIPTION
	----------------------------------
	ON	0C0000-0C7FFF	On Board EGA BIOS enabled(32 bit access)
		0F0000-0FFFFF

	OFF	0E0000-0FFFFF	BIOS On EGA Card selected(8 bit access)
	----------------------------------

Not sure if that helps but that PDF should.

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LoganB, that document is gold, thanks ... page 55 (relative to the PDF) has a memory map with info on how 64K ROM windows are repeated at different addresses ... but it's beyond me to translate that into MESS code.


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
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VM/PC software for XT/370 failing to run on a regular XT:



Not a WIP :-)

Manual: http://classiccomputers.info/down/IBM/IBM_Misc/IBM_VM-PC_Users_Guide_6361530.pdf

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wow, nice :-D

Why no WIP? No documentation for the add-in cards, I guess?

Last edited by Darkstar; 01/11/17 08:27 PM.
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"XT/370 Technical Reference" p/n 6936732 did exist, but it's not online. But I'm scared of real IBM hardware smile Displaywriter is complex enough, and it's just a x86 machine...

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Can still softlist the disk and skeleton the card ROM for now smile

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All I have is a zip file with installed copy of VM/PC... no boards.

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Interesting article about the XT/370 here: http://www.cpushack.com/2013/03/22/cpu-of-the-day-ibm-micro-370/

Amazing that they used custom microcode on the 68k.

"[IBM] had Motorola implement most of the System/370 instructions in a new microcode (developed by IBM) for the 68000. Nick Tredennick of Motorola worked with IBM to implement the microcode 68000 structure. Nick had previously developed the logic design, and microcode for the original Motorola 68000 processor in the late 1970’s so was very familiar with it. Not all of the instructions could be made to fit in a 68000 so a second, generic, 68000 emulated them in software. Floating point instructions were implemented in a similarly customized Intel 8087 FPU. These 3 chips were on a card called the PC/370-P. Two other cards were required called the PC/370-M (Memory) and PC/3277-EM which made the system appear to be a 3277 terminal. These 3 cards together implemented a System/370, albeit slowly."

Here is a PDF from IBM Systems Journal 1984: http://maben.homeip.net/static/S100/IBM/...%20computer.pdf

Reminds me that I should really visit the IBM lab/museum in Böblingen at some point, seeing as it's only a 15 minute drive from here...

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A 68000 that doesn't run 68k instructions plus a normal 68000 plus an 8087 that doesn't run x87 instructions?! I'm simultaneously impressed and repulsed.

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