The 1572 Dual Disk Drive

[airship]

Did any of the prototypes for the 1572 drive ever make it into anyone's collection?

It's the bottom device in this pic:



Here's what it says on the Secret Weapons of Commodore site ( http://www.floodgap.com/retrobits/ckb/secret/periph.html ):

The 1572 was first introduced CES 1985, according to Jan Neuvians, and is essentially two single 1571s stuck together in an oversized case. Unlike regular dual drives like the 8050, it has two controllers (not one) as well as two mechanisms, which seems to imply that again unlike regular dual drives the drives were addressed as device 8 and device 9, not as device 8 drive 0 and device 8 drive 1. It also has somewhat more RAM (8K) and ROM (a whopping 64K), and was intended for fast backups with a maximum capacity of 410K. Note that released 1571s have only 2KB RAM apiece, not 4KB, but the manual states 4KB which explains the discrepancy. Interestingly, version 3.0 1571s may have a remnant of the 1572's fast backup capability in them. According to Martin Brunner, two 3.0 1571s can be connected and a backup from eight to nine completed within a few seconds. Unfortunately, the version 3.1 ROM in the DCR and later 1571s no longer has this feature, and it is not tripped with the old PET-era DUPLICATE command, so no one is quite sure how to kick it off. It is not likely that the 1572 ever saw the light of day.

Has anyone ever done what was apparently NOT done in the 1572? That is, has anyone produced a ROM version for the 1571 that would allow it to operate two drives like the old PET drives, as devices 0 and 1?

Also, as I have two 1571s with the v3.0 ROMs, I'm obviously intrigued by the assertion that the fast backup capability might be in there somewhere. Has anyone seen the software that allegedly does this? Does anyone know this 'Martin Brunner' guy?

[airship]

I've been in touch with Martin Brunner (who, by the way, runs a great site called 'C64 Game Solutions' at http://c64.tin.at/ ) and here's what he has to say on the topic:

"I only heard this rumor and never copied a disk this way since I never had two 1571s with version 3.0."

So it's just hearsay so far. Anyone have anything more solid on this?

[nikoniko]

Any chance you have a dump of the 3.0 ROMs? We could do a comparison with 3.1 and see if we can come up with the alleged feature.

[airship]

Sorry. I'm not sure how to even dump the ROMs on a 1571. Hints?

Also, I guess I'm not sure they are even 3.0s to tell you the truth. I might have assumed that when they didn't return as 5.0s. I'll recheck and let you know.

[Golan Klinger]

Download a copy of Drive Memory Dump and away you go.

[Guest]

Sorry. I'm not sure how to even dump the ROMs on a 1571. Hints?

If you have a copy of Fast Trac\128 by Mike J. Henry, it has a Monitor that will transfer drive memory to the computer.

Also, if you have or know someone with an Eprom Programmer, you could pull the rom out of the drive (it's in a socket), read the Eprom and save the file to disk.

Dan...

[8502]

No need to dump the 1571 ROMs as they're already available at http://www.zimmers.net/anonftp/pub/cbm/firmware/drives/new/1571/index.html

Unfortunately, both the 310654-03 and 310654-05 ROMs identify themselves as cbm dos 3.0.  The 318047-01 is the 1571cr ROM and identifies itself as cbm dos 3.1.

The book 'Anatomy of the 1571 Disk Drive' (US title: '1571 Internals') mentions the fact that the 1571 dos is derived from the earlier (PET era) 4040 dual drive, which did have drive 0 and 1.  It also contains a complete annotated disassembly of the 310654-03 firmware (which is pretty heavy reading :/ ).  If I have the time, I'll look for evidence of a 1572 mode and post my findings  

cheers,
paul

[airship]

Thanks, Paul. At INFO we used an 8250 dual drive (hooked up to a B128) as well as an MSD-2 dual drive, and I've got to say they are 8x more convenient than using two individual drives. Just having the COPY command available is invaluable, and of course you can copy full disks like lightning. We had the MSD-2 set up as a stand-alone disk copier - you downloaded the copy program to the drive, disconnected it from the C64, and just stuck two disks into it anytime you wanted a copy. It detected disk insertion and did the copy for you automatically. How convenient is that? Especially in our environment, where we often traded disks with screen shots, text files, and even programs we wanted to review.

A dual 1571, i.e. 1572, would be sweet.