Software for IBM 36030 was DOS360: Forty years 515

Can't be either one: neither the F or D versions of the COBOL compiler were ever "rented" -- for that matter, neither one was even copyrighted.

Other than a few specialized applications, the majority of software packages written by IBM were available at no charge to IBM customers, and non-IBM customers could either get copies from other shops, or pay for the reproduction costs and get them from IBM. All this changed, of course, with New World (June 1968 plus 1), but that didn't alter the status of products relased prior to that date.

See the above: pre-New World, for most software IBM didn't charge anyone.

I never worked with the 1401 emulator; how did the emulated 1311s map to a 2314? I do recall (under OS-360) needing to recover files from a DASDR dump of a 2311, and did so by restoring the 2311 image to the 2314, then under OS-360 patching the device characteristics to match the 2311's geometry. This wasted a lot of space, but needed to persist only long enough for me to copy the files onto a normal 2314.

You are being *FAR* too kind to the 2415. It was, of course, the S-360 version of the 7330 tape drive, which was

Umm...perhaps I shouldn't use the words that truly describe the 7330 or 2415 in a family newsgroup.

That's an issue with the channel architecture. A tape drive would be placed on a selector channel, which permitted only a single operation to be active. Once something causes I-O to start on a selector, no other I-O operation can be started until the first has terminated and the trailing interrupts serviced. buttuming that your two tape drives were on the same control unit and channel, in this case your problem isn't the tape drives' fault.

Joe Morris