Re: Virtual Tape format

Hello Joe,

Am 29.09.2025 um 19:59 schrieb Joe George <jgeorge@xxxxxxxx>:

I have a number of physical IBM SL tapes I need to get the data off of in a format where I can transport them over the internet to someone else.

The data on the tapes is exceedingly rare. I need to 1) Digitize them in ANY kind of reconstructable format, and 2) Get them in some kind of interchange format other people without AS/400s can use.

I faced a similar issue. I've read tapes with the already mentioned duptap program suite (having been a free part of the QUSRTOOL library for V3R1) on an AS/400 and wrote them to a DDS drive from the duptap files. From there I transferred the DDS cartridges to a PC with a DDS drive, running Linux, and read the tape there with Hercules provided AWStape reader.

I haven't found a way to reliably test if what I've fabricated is indeed working.

They are mainframe data, and most modern mainframes and emulators can cope with AWSTape format

Oh. From the README:

---8<---

This tool allows duplicating a tape using a single tape drive.

The tool only supports tapes written by Save commands or IBM distribution. Tapes written in data interchange format are not supported.

The PTF tape has a combination of Save format and interchange format. DUPTAPIN can be used, but the handling of the data interchange files will not be correct.

---8<---

I don't know about real world implications.

2) is harder. I don't know what the actual file format is of the virtual tape volumes, so I need to find some way to convert those virtual volumes to something like AWSTape.

I presume, like many things from Rochester, we're not supposed to know, but only use. No public documentation available. AFAIA.

I can use a PC running a mainframe emulator to read the tapes directly into AWSTape format (there are dos/Mac/linux utilities do to this), but I don't have a way (currently) to hook an HVD Differential SCSI tape drive up to a PC with an LVD SCSI card in it. Which is a different problem altogether.

Converters exist but are becoming increasingly scarce. It might be easier to find an older HVD card. Did a search and…

https://www.disctech.com/Adaptec-2944UW-Ultra-Wide-HVD-SCSI-Controller

Not too pricey considering this being a very niche product.

Note: I'm not affiliated with the seller. It was just the first reasonable link Google turned up.

I was just hoping that there was documentation somewhere for the virtual tape format used in image catalogs, so I didn't have to read these old tapes down more than once.

See above.

:wq! PoC