During the last year, several hardware additions and alterations have been made to the PDP15. Machine usage has steadily increased because of FR80 support programming and the addition of new staff and external users.
The LA36 is a high speed, wide-carriage teletype which operates at 300 baud and serves as a slow lineprinter for short listings. It has upper and lower case, but most DOS subsystems only recognize upper. As it is interfaced to the LT19 interface, it is known as device LT2. LT19.devices have been renumbered as follows:
LT0 Tektronix LT1 VT15 console keyboard LT2 LA36 DECwriter
The Tektronix interface has been modified to work at 9600 baud from the PDP15, making it an attractive listing and graphics alternative to the VT04 refresh display.
A new switch has been installed on the PDP15 cabinets to allow the Tektronix to be used on either the PDP15 or the 1906A. The two position switch on the cabinets selects the PDP15 or 1906A interface. As the two interfaces have different characteristics, the communications switches on the bottom of the Tektronix cabinet must also be set properly as follows:
Device BAUD RATE, Send - Receive LINE TYPE CARRIAGE RETURN
PDP15 9600 BAUD NORMAL FULL DUPLEX CR-LF
1906A 1200 BAUD LOCAL COPY FULL DUPLEX CR-LF
Because a software fault in the PDP15 has been cured, all Tektronix (and DECwriter) switches can now be operated without disturbing a running PDP15 program.
In order to facilitate the display of half-tone pictures on the VT04 display, the hardware character @ (1008) has been redefined as follows:
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The character, called DIXEL, may be used just as any other VT04 hardware character. It will produce a rather different, though not annoying, horizontal spacing if it occurs in a text string.
Used as a plotting character, it produces a reasonable scanned-line image with reduced flicker.
At last. Although a stubborn hardware fault still has not been corrected in the BSI interface, its low frequency of occurrence and recoverability suggests that the BRSI is now reliable. Software is available (now being documented) to transfer source files across the link in both directions. The impact of link usage on 1906A efficiency is now being examined.
The daily use of the PDP15 has grown steadily, there now being about a dozen regular programmers and many occasional users. This trend seems likely to continue and will require everyone's patience as new working procedures and, sadly, a necessary amount of red tape are instituted. Every effort will be made to keep working arrangements as flexible as possible. Suggestions for allocation of machine time and space will be gratefully accepted by WDS.
Until new procedures are worked out and distributed, the following suggestions are made with a view towards saving time and frayed tempers:
(1) Book time on the PDP15 no more than a day in advance, except for important demonstrations, etc.
(2) Unless the job requires it, book only an hour block at a time.
(3) Consider working an occasional evening if you can make the arrangements.
(4) If an occasional user wants 5 minutes to VIEW or examine a magnetic tape, try to arrange it at the end of your time period.
(5) If your work requires less than an hour, book less.
(6) Large amounts of program input and typing can be done on the 1906A and transferred to the PDP15 using paper tape or the BSI.
(7) Try to keep disc areas as small as possible by deleting files which can easily be regenerated. (BIN files, XCT, XCU, LST Fi1es). Use UPDATE to combine binary files; it saves time and space in the long run.
(8) Directory SCR (scratch) may-be deleted at any time to provide additional disc space.
(9) Do not generate a multitude of pseudo-UIC's for yourself and leave them on the disc. (If you do not know what a UIC is, then do not worry about it). Each UIC increments the overhead on all user disc accesses, takes up extra disc space and confuses the systems programmers. Two UIC's should be sufficient for most cases, especially since SCR may also be used.
(10) Report faults with date, time and initials in the hardware log and notify WDS, LOF or JRG.
(11) Useful information appears on both the bulletin and white boards.
(12) Before leaving the machine:
(a) LOGOUT
(b) Turn TTA, DECwriter and magnetic tape deck power off.
(c) Tear off your listings and dispose of them. Paper placed in the square bin will be recycled - do not crumple it up.
(d) Make sure you have not left anything. Unknown listings, papers and magtapes will be disposed of.
Initials Name Telephone Room/Location
AJH 'Hank' Hancock 6384 1906A Operations
AHF Alan Francis 346 F34
AWB Tony Burraston 6380 G12
GVD Gordon Dawson 6387 F29
IB Irene Buchanan 6619 F30
JAH Jean Hambleton 6384 1906A Operations
JMR John Rushby 6235 F32
JRG Julian Gallop 6235 F32
LOF Len Ford 346 F34
MDD Mike Davies 542 G30
MJS Mike Stapleton - RCA
RET Eric Thomas 6219 G10
RWW Rob Witty 6218 G13
TRA Trevor Amos 6384 1906A Operations
TRP Tira Peart 344 F31
WDS Wade Shaw 6218 G13