Dts romdos

[Marco Giustini]

Hi all

I know that earlier DTS units had a ROMDOS card and if not mistaken that was to be removed if the CD drives were replaced.

I believe the ROM contained some sort of DOS which basically booted the unit which would then look for discs. The software (DTS.EXE) would then be loaded from them.

Without the ROMDOS, where did the players boot up then? Directly from the Discs?

Thanks!

[Gordon McLeod]

No they added the aquilla card that started the boot cycle

[Marco Giustini]

Memories!

So, re-reading the troubleshooting manual after ages, this is my understanding:

- All the DTS players boot from a ROM chip. Then they load the DTS.EXE from the discs.
- With old Toshiba drives the ROMDOS chip was installed on the timecode board D422 and it was a 1Mbit chip
- Wit TEAC drives, the ROM became 4Mbit. Likely the D422 did not support such large chip so a new board called "ACQUTEK" was installed with a new ROM which can be called ROMDOSB (for 16x drives) or "AQRM (for 32x drives).
- A system would have ONE ROM, EITHER a ROMDOS on D422-U12 *OR* A ROMDOSB/AQRM on a separate ACQUTEK card

One of my DTS units indeed has the PM-8002 card which happens to be an ACQUTEK card (it's a cheap ROM card!). It has a ROMDOSB chip on it so I assume my drives are 16x (haven't checked yet.

Bottom line: all DTS units used to boot from ROM. It makes sense as
1. Booting from CDROM might not have been possible in 1993
2. Botting from CDROM would mean an error message if discs were not found, requiring a reboot (with the ROM boot, the software would pause and wait for a disc and then load DTS.EXE when found).


https://user.xmission.com/~acqutek/usa/pm-8002.htm

image_2042.jpg

IMG_0087.jpg

[Marcel Birgelen]

It's all based on a basic Intel 386/486 architecture and as such, you'll always need some kind of ROM or BIOS to boot. The CPU itself does know nothing about how to interface with the CD-ROM, so you need to boot a basic operating system environment, like any of the DOS systems available for the platform. Once the system is booted, it would read the latest DTS.exe from the discs.

Those old CD drives at first needed their own interface cards, you couldn't just hook them up to your P-ATA/IDE bus. Some sound cards back then supported several of those CD-ROM interfaces. SATA wasn't even a thing back then and SCSI was way too expensive. So, your BIOS had no clue how to even access those drives.

Maybe you remember the old MS DOS days where you needed to load a specific device driver in your config.sys and autoexec.bat to access your CD-ROM drive as a drive letter. Those drivers were usually provided by the CD-ROM drive manufacturer, especially in the days with non-generic interfaces. Same thing here, only in an embedded environment, where the OS isn't on a hard drive or floppy, but on a ROM chip.

Nowadays, it should be entirely possible to boot the system directly from CD-ROM, but as you indicated, those features only became available with more modern BIOS implementations and a standardization of the CD-ROM interface on P-ATA, S-ATA and SCSI interfaces.

[Marco Giustini]

Thanks Marcel

I’m aware on how msdos used to work, it’s just that I never really understood how the 386/486 based DTS players were dealing with that, mostly because - I think - the manuals were not explaining much. Never understood what that ‘Acqutek’ card was and what the ‘AQRM’ chip was. Now I looked into that again 20 years later, it’s very clear.

I’ll plug a VGA card and see what’s inside those ROM disks. I’ll also make an image and share it here when I have a chance.

I also understand the hassle of using off-the-shelf pc parts there: every time drives were updated with new models you needed a different SCSI card as the protocol had changed meanwhile and the older cards were not compatible anymore.

Thanks again!

[Blaine Young]

I've outfitted all of my 6Ds with VGA boards for easy diagnosis.

[Marco Giustini]

Me too, when I used to use them. The "queue" field was pretty useful!