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#111272 - 11/14/17 06:21 AM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
Joined: Dec 1999
Posts: 1,162
Justin Offline
Very Senior Member
Justin  Offline
Very Senior Member

Joined: Dec 1999
Posts: 1,162
Vancouver Island, BC, Canada
So I've recently started adding some more copy-protected PC software to the ibm5150 softlist. MAME has had varying support for copy protected PC disks for a while now in formats like TD0 and IMD, but these require a working DOS PC to run the imaging software and the formats are proprietary and undocumented which is not great for preservation. The Kryoflux board works for reading the disks on modern PCs but produces raw files which can't be used in MAME directly. (MAME can read SPS' IPF format but the software that produces these from raw Kryoflux dumps is not public.) However, it is possible to convert these files into a format usable in MAME by using a free utility called HxCFloppyEmulator. Here's a tutorial:

1. Download HxCFloppyEmulator_soft.zip from http://hxc2001.com/download/floppy_drive_emulator/

2. Run the GUI and click the first "Load" button (NOT the raw one)

3. Select the first .raw file (e.g. track00.0.raw)

4. Wait for the progress bar to finish

[Linked Image]

5. Click the "Export" button

6. Select "MFM File (MFM/FM track file format) (*.mfm)"

7. Enter a filename (e.g. disk1.mfm) and save

8. You should be able to load the .mfm file as a normal disk image in MAME. With the copy protections I've tried so far everything has worked fine and the software thinks it is running from an original disk. (As I understand it the PC floppy controller didn't allow for the really creative copy-protection methods seen on other systems like Amiga and Apple II.)

Obligatory screenshots:

Space Quest II (from my own disks, now added to the softlist):

[Linked Image] [Linked Image]

Microsoft Word 1.15 and 2.00 (dumps available online, and added to the softlist as well):

[Linked Image] [Linked Image]

#111312 - 11/20/17 11:41 PM Re: PC/XT/AT (inside) WIP topic [Re: Kale]  
Joined: Jan 2012
Posts: 780
rfka01 Offline
Senior Member
rfka01  Offline
Senior Member

Joined: Jan 2012
Posts: 780
Bavaria
In post #111233 I presented the Compaq Portable III and linked to a site that claims that its graphics card is compatible with the AT&T PC 6300/Olivetti M24 (640x400 monochrome, enhanced CGA, not-quite-EGA). Deriving from IBM 5170, the BIOS slots in nicely, and I gave it the m24_cga graphics card and the hdc hard disk controller which let me install DOS without a hitch.

A good test case for graphics compatibility is Windows 3.0 as it contains drivers for the Compaq 640x400 pixels Plasma screen that is used on the Portable III and its successor, the Portable 386.

[Linked Image]

After the text mode install, Windows tries to switch to graphics mode, and you can see it opening ... ahem ... Windows, but it fails to fully switch to graphics mode, leaving me with that colourful screen with lots of blinking characters.

[Linked Image]

If you launch Windows after one such botched installation attempt, you can see the boot screen in monochrome CGA for a fraction of a second, then the green text screen appears.

Time for a cross check: On the Olivetti M24 driver, the Windows installer correctly recognizes the AT&T/Olivetti graphics adapter, installs in text mode and then switches to graphics mode.

The coup de grace, however, is: If you install Windows 3.0 in the Olivetti M24 driver using the Compaq Portable Plasma setting, Windows works just like with the proprietary Olivetti setting.

[Linked Image]

John Elliott gives some hints on the peculiarities of the Portable III's video system - I'd love it if some minor tweak by a kind dev would allow the M24 adapter to be repurposed as a generic AT&T PC 6300 "super CGA" adapter - Team E's just dumped two early Nixdorf 286 Laptops that used that same chipset.

Under "Machine configuration - CGA monitor type" you can set different displays, e.g. an LCD - but the actual MAME display doesn't change. What additional steps are necessary to get the LCD screen simulation that is used in some drivers - and do we already have a red/amber plasma screen emulation?


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
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