PmWiki | Emulator / PC8E

Class: PC8E, PtrPtp

PC8E Reader/Punch emulation

This is how the PC8E looks in my emulator. At the left is the reader part with emulated fan-fold tape and at the right the punch part also showing the fan-fold tapes, but from another perspective. At the far right the switches positioned as in the original.

The tapes move in a realistic way for the 2 units (reader and punch) implemented. The tapes appear when the tapes are allocated; the punch also shows the holes as they are punched.

The various modes are selected by right-clicking on the window. For the reader one can select a normal speed and a high speed; the high speed is 10 times faster than the normal one (300cps). For the punch a high speed mode and also a 7 or 8-bit mode can be selected. The 7-bit mode was provided in order to be able to export ASCII data without the bit 8 in order to be compatible with the PC platforms (see ASCII code).

The emulation is based on the characteristics of the PC8E controller board and of the PC04 physical device. This hardware is detailed in Small computer handbook Chapter 6-10 and Maintenance Manual Volume 3-2.

The only available copy of the Maintenance program was of such a bad quality that this program was retyped and reassembled (the new version in the next table).

Program Name	Maindec	Remarks
High-Speed Reader-Punch Test	MAINDEC-08-DHPCA	Original Test Program: DHPCA.SV on disk/tape
New High-Speed Reader-Punch Test	MAINDEC-08-DHPCAB	Rewritten Source: DHPCAB.SV on disk/tape
All-Zeros Test tape	MAINDEC-00-D2G1	Test paper-tape: under PDP8.Tests
Ones-Zeros Test tape	MAINDEC-00-D2G2	Test paper-tape: under PDP8.Tests
Special-Binary Test tape	MAINDEC-00-D2G4	Test paper-tape: under PDP8.Tests

In order to test the reader/punch you will need some of the test tapes shown above.
A small modification of new test program was made by incorporating a small patch (1240/1646 7200). This was necessary because in some steps of this program a punch file was created with a small text passage (Showing UP on the tape). Because I cannot position the tape in the reader accurately, this text was replaced by blanks.
Boot the PDP8 with the Build-11-03-07 from Disks.Working m43 volume, then start the test program (DHPCAB.SV) from the Myprogs disk. Now follow the next steps of the test. Do not forget to put the emulator on "PDP8 speed" for the timing tests. The program number in the following table should be set in the switch register.

Program	Function
00	BASIC READER AND READER CONTROL LOGIC TEST
01	BASIC PUNCH AND PUNCH CONTROL LOGIC TEST
02	READER TEST, SPECIAL BINARY COUNT PATTERN
03	PUNCH TEST, SPECIAL BINARY COUNT PATTERN
04	PUNCH VERIFY, BINARY COUNT PATTERN
07	COMBINED READER - PUNCH TEST
13	READ SPEED PRINT LOOP
14	PUNCH SPEED LOOP

Other steps do also run correctly but do not add anything new.

A good starting point for using the emulator is to mount the disk Build-11-03-07 from Disks.Working on unit 0 Fixed. The tests used are located on disk MyProgs-22-04-07 of Disks.Working in .SV format and can be mounted on unit 0 Removable. Go to Disks.Working and download to a directory of you choice. You can then always mount these disks from this location. Don't forget to write-enable this directory and all of its files!