On 6/26/2015 12:10 PM, Timothe Litt wrote:
On 26-Jun-15 13:43, Hittner, David T (IS) wrote:
What PDP-11 used TU58’s, and what controller did the drive connect to?
Dave
11/23, 11/44, VT103, HSC50 -- among others.
Host: Any RS232/423 (dumb) interface, e.g. DL(V)11, MXV11. 9600 - 38400 BPS
using a packet protocol (RSP, IIRC) with XON/XOFF flow control
The drive itself has an embedded 8085 CPU that is the real controller. It's
not terribly smart.
The protocol is roughly similar to MSCP (lighter-weight); the tape is
block-addressable, normally the 512 byte DEC standard block, although there's
a 128 byte record mode for dealing with buffering/comm issues. Normally the
controller assembles 4 records to make a block. Cartridge is formatted with
512 blocks of 512 bytes each (0.25 MB).
http://bitsavers.trailing-edge.com/pdf/dec/dectape/tu58/ has the docs.
As indicated the physical TU58 controller connects to a plain serial line
interface on the PDP-11. A DL11-W works fine for example. It uses just RS232 TXD
and RXD, no other sideband signals. The TU58 serial interface wants to be a
776500/300 on a PDP-11 for software compatibility.
The DEC DL11 serial boards run at 9600baud (normally the fastest) which works
for the TU58 emulation, but is a bit slow. Boots XXDP diag in about 2 minutes.
The PDP-11/44 has an integrated TU58 serial port that can run at 38.4Kbaud,
which makes it a more usable configuration.
It is possible to (reversibly) modify a DL11-W to run at 115.2Kb (replace UART
chip, bypass baud divider, new oscillator) that runs very nicely on a PDP-11/34,
for example. Boots XXDP diag in about 15 seconds.
There is a command line program for Windows/CYGWIN, MacOSX, and Linux that
emulates a physical TU58 drive controller, up to eight units.
The source and Windows executables are now hosted here:
https://github.com/AK6DN/tu58em
I also have a web page that has a number of useful XXDP diagnostic tape images
for various PDP-11 systems: https://ak6dn.dyndns.org/PDP-11/TU58/
I tried early on to configure SIMH with a DL11-W style serial port and connect
TU58EM running as a separate process and got it to work, sometimes.
This was a long while ago (a few years) and I have not tried it since.
It probably would not be a big programming project to build a direct TU58 add in
controller into SIMH. The documentation all exists on bitsavers.
Note that booting a physical VAX-730 requires a functional TU58 in the system
(either real tape drive or emulated tape drive via TU58EM).
Mark Blair just recently revived his 11/730 and got it to run diagnostics and
boot VMS using a slightly modified variation of TU58EM running on MacOSX.
The VCF forum:
http://www.vintage-computer.com/vcforum/showthread.php?36113-Problems-using-tu58em-with-VAX-11-725-VAX-11-730
describes all this.
Don
This communication may not represent my employer's views,
if any, on the matters discussed.
*From:*Simh [mailto:[email protected]] *On Behalf Of *Bill
Cunningham
*Sent:* Friday, June 26, 2015 1:14 PM
*To:* Hans-Ulrich Hölscher; [email protected]
*Subject:* EXT :Re: [Simh] TU58 device for PDP-11s
----- Original Message -----
*From:*Hans-Ulrich Hölscher <mailto:[email protected]>
*To:*[email protected] <mailto:[email protected]>
*Sent:*Friday, June 26, 2015 12:56 PM
*Subject:*[Simh] TU58 device for PDP-11s
Am I right that there is currently no TU58 device available for the
PDP-11 series of computers?
If so, would someone be so kind as to implement it?
Thanks in advance to all programmers who ponder on evetually doing it!
Regards,
Ulli
I don't know about simh, but there are several simulators out there.
There is something for linux too. But it sounds like a worthy cause.
Bill
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