Simulated disk drive for RT-11?

On 6/3/05, David Betz <dbetz at xlisper.mv.com> wrote: Yes. The TU58 drive is strappable, but 38Kbps is a standard speed. Yes... I know it's written up in several DEC manuals, some of which are probably on bitsavers. The basic protocol is called "Radial Serial Protocol" (RSP), but, I think, for newer implementations, like in the firmware of a VAX-11/750, there are some variations that, while documented, aren't as easy to find as the base documentation. It's ordinary to hook a real TU58 on a port of a DLJ11J... one can even use a straight-through 10-pin Berg cable - it's the same pinout (one of DEC's standards). It's also possible to emulate a TU58 on a modern PC, or to hook up a real TU58 to a modern machine to read tapes. I don't have my tools with me, but googling for TU58 and emulator will probably cough up something interesting. Media size is a bit of a problem - a real TU58 is kinda small, even compared to an 8" floppy. Speed isn't great - at least an emulated drive doesn't have seek delays, but transfer speed becomes the bottleneck. OTOH, there are drivers for RT-11, and it _is_ a simple device to emulate. If only it were a few megs in size, it would be adequate for quite a few applications.