Die CPU Teletypte ASR 33 Tektronix 555 CPU DEC-Tape TU56 RK05-Drive
Computermuseum der Fakultät Informatik				german


General view of the lab8/e

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Lab8/e in general view                          <<<    ***    >>>    ^^^


The successor of the PDP-8/I resp. PDP-8/L was the PDP-8/E. It is
still in TTL technology and equipped with a core memory. The case of 
the CPU has the same dimensions like the PDP-8/L. This computer was 
also available as a pure tabletop machine. By advance of the 
semiconductor technology, many extensions (peripheral controllers, 
main memory full extension, extended arithmetical unit) formed this case, 
which had to be placed in extra slots of the PDP-8/I. The PDP-8/E was
used by the Institute of Plasma Physics between 1971 and 1985 and was
extended more and more in the course of time. Thus it was not equipped
with 32k from the beginnng but was extended year by year in 4K steps.
Anyway 4K main memory cost 10.000DM.
Some peripheral devices for the PDP-8/E are: A tape drive TU56, a 
removeable disk RK05 with 2* 1,2 MWords, a Plessey removable disk, 
a high speed punched tape card reader, three serial interfaces where a 
Teletype and another terminal could be connected with, a Votrax 
Speechsynthesizer as well as an interface for the display of graphical 
informations on an ordinary oscilloscope. In the strict sene, it is a  
LAB-8/E, a special realization of the normal PDP-8/E which was pre-
configurated for the use in scientific laboratories: The machine 
contains a D/A and an A/D converter for measurement value logging as 
well as several digital in- and outputs to query switching positions 
and threshold generators automatically and to controll relais, 
valves and motors. The main use of this computers was finally 
the process control. 
However, these computers have not been delivered as a finished system,
but they could be constructed and extended by the construction kit 
philosophy almost completely free: You eventually started with the CPU
on the desk with a 4K main memory and a Teletype. Then, a 19"-rack was
purchased and a DEC tape drive was added. Memory could be 
purchased by 4K steps.
By the good technical documentation it was possible here it was 
possible to customize the system with selfmade hardware extensions to 
your own requirements. Also the OS/8 operating system was that well 
concepted, so that drivers, which the user has written for new 
devices on his own, dovetailed perfectly with the system.

Operating systems:
Many were available for the PDP-8. Originally, the computers were used in
pure batch mode: A program is loaded from punched tapes and executed.
Then the computer interrupts. By the wide circulation of the DEC-tapes
and disks it then was possible to create real operating systems.
Presumably the most widely spread was the PS/8 res. its successor OS/8. 
It requires at least an 8K main memory, its resident part, that means 
the permanently allocated memory is only 256K words.
Its operation is adapted from the mainframe computers of the PDP-10,
many service programs for example the TECO(a texteditor), RUNOFF
(a text formating tool), PIP(a peripheral usage tool) exist for both 
platforms and were later ported to others.
Who already knows OS/8, will also simply find one's way on a PDP-10 
with RT/11. OS/8 and Tops10, the operating systems for the DEC-
mainframes PDP-10 also inspired other operating systems, for example
CP/M and MSDOS.


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