Pertec T8640A Tape Transport

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I have a Pertec T8640A Tape Transport that is now working nicely on a QBUS PDP-11 system.

While I still have a lot to learn about the operation of magtape systems (and their advantages and limitations), I am now able to successfully “INItialize”, write to and read from magtapes in this Tape Transport.

This Tape Transport is currently mounted in a full-height DEC rack. The rack also has a General Robotics QBUS chassis in it, as well as an MPI CMD Model 9448 hard drive. I’ve not been able to find any information about an MPI 9448, though there is a brochure on the web about a CDC 9448, which appears to be the same drive. The CMD drive actually has a 16MB fixed hard drive and a removable 16MB cartridge drive in the one enclosure. The removable cartridge is a Nashua 4420, and is not compatible with DEC removable-media drives. I have not yet got the SMD drive working.

The QBUS chassis is fairly well equipped. It includes:

  • M8192 processor
  • [RAM board]
  • 2 x Webster terminal multiplexers
  • 2 x DEC DLV11-J 4-port SLU board
  • An Emulex SC02 board to support the SMD drive
  • An Emulex TC01 (2-board set) to support the Pertec T8640A Tape Transort

The Tape Transport has 3 x 36-pin edge connectors on it. An Emulex cable kit connects 2 x 40-way ribbon cables to these edge connectors. At the other end of each of the Emulex cables is a 40-pin header connector (so two 40-pin header connectors in total). These two header connectors have handwritten notes on them that say respectively “long board” and “small board”, suggesting that they perhaps connected to a 2-board interface of some kind?

Photo Gallery

Here are some photos of the Tape Transport and the rack in which it was found.

Here are some photos of the Pertec Formatter (I am not sure if this is part of this system).


I have the following hard-copy manuals:

  • Models T8640A and T8660A Synchronous Write Synchronous Read Tape Transports, Operating and Service Manual No. 103381
  • NRZI Formatter Model F8X9, Operating and Service Manual No. 101600

Tape Transport

The Tape Transport has 3 x 36-pin edge connectors numbered J101, J102 and J103.

The diagram on the right shows the pinouts for these connectors. It is page 2-6 from Manual 103881.

Pertec Formatter

Unfortunately this Formatter does not have any manufacturer name or model number on it, except for the “Pertec” badge on the front panel. It does however look very similar to the formatter shown in the F8X9 Manual listed above. So for the time being I assume that is what it is.

The F8X9 Formatter has 2 x 100-pin edge connectors numbered J101 and J102. J101 connects the Formatter to the Controller. J102 connects the Formatter to the Tape Transport.

The diagram on the right shows the pinouts for these connectors. It is page 2-4 from Manual 101600.

This formatter does not appear to be part of this system. I do have two other Pertec T8640A tape transports (without the 3rd borad, which is for 1600 BPI), and I assume this formatter was intended to be used with one of them.

“Pertec Interface”

I am aware that tape drives on PDP-11 systems usually have two 50-pin header connectors (referred to as the “P1” and “P2” connectors).

Chuck Guzis has a webpage that describes the pinouts for the Pertec Interface.

A typical interface board for tape drives is the Dilog DQ132 board. I don’t have a manual for the DQ132, but I do have a manual for a DQ130.

Loading RT-11 on to magtape

Copying RT-11 on to the magtape was easy.

Here are the commands:

  • INI MT0:

However the COPY/BOOT command (COPY/BOOT MT0:RT11SJ.SYS MT0:) does not work. Need to work out how to make a magtape bootable.

Next Steps