[pups] New Release of VTserver program

Warren Toomey wkt at henry.cs.adfa.edu.au
Mon Mar 26 12:14:44 AEST 2001

All, I spent the weekend working on my VTserver program, which lets you
copy disk images in/out of a PDP-11 without a tape drive. It's at

Could I get anybody with a PDP-11, 256Kbytes of core, and no tape drive
to try this out. I'm keen to find out which -11 models it does or doesn't
work on. Also, if you have less than 256Kbytes of core, please let me
know if you want Vtserver to run on your platform. If there's enough
interest, I'll try to rewrite the code to fit in a smaller footprint.

At present, Fred van Kempen is also working on adding VT support to
Ultrix-11. When he's done, we will do a merge of the server, and add
his Ultrix client code into a separate directory of the VT distribution.

Attached is some more blurb from the README.

The Vtserver program provides you with a method of copying a disk image into
a PDP-11, or extracting a disk image from a PDP-11, without a tape drive or
indeed an installed operating system.

The approach here is use a nearby Unix or Linux computer as both the PDP-11
console and as a virtual tape server. The VTserver software comes as two
components: a set of PDP-11 software which acts as the virtual tape client,
and the server which is hosted on the nearby Unix machine. The two computers
are connected via an RS-232 null modem with hardware handshaking.

I've used the Ersatz-11 2.0 demo simulator with various
CPU models, and RL02 and RK05 disk images, to test copy. Here are the
results: copy can read and write disk images for /24, /34A, /40, /44, /45,
/70 and /94 systems when they have 256Kbytes of memory. It doesn't work for
the 11/35 as it doesn't have the MUL instruction, which the 2.11BSD C
compiler generates.

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