Chilton::ACL::SPROGS Technical Paper

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⟶ ACL ⟶ Literature ⟶ Progress Reports ⟶ SPROGS Technical Papers

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Applications Associates Literature Society Technology Software revisited

Early history □ Minutes of committee meetings □ Progress reports □ Other reports □ News cuttings □ In-house publications □ Committee papers □ Personal recollections □ ACL publications □ Books □ Early Atlas publications □ FR80 reports □ Atlas manuals □ ICL1906A manuals □ Other manuals and papers

General □ Applications Software Group □ Basic Software Group □ FR80 □ FR80 operations □ FR80 project notes □ FR80 technical notes □ FR80 user notes □ Graphics □ Graphics Section □ Graphics Notes □ Graphics User Notes □ PDP15 □ PDP15 Notes □ SPROGS □ SPROGS Technical Notes □ SPROGS Papers □ SPROGS Notes

SPROGS Technical Paper No 15: PDP15 Hardware Changes

J R Gallop

3 January 1974

Change in VT15 addressing

Previously the VT15 could only address indirectly in 32K. In order to be able to create display files in store above 32K, an ECO has been added to allow the indirection mechanism to use 17 bits.

The graphics routines VTPRIM and FOG have therefore had to be changed and there is now a new version (005) of VTPRIM on the system library .LIBR BIN.

This affects existing programs as follows:

(i) Programs made available as an overlay system will not work and must be reCHAINed (example FONTS and VIEW)

(ii) Programs made available as a relocateable binary file using explicitly a previous VTPRIM must use version 005 by allowing it to be loaded from the library (ie do not explicitly load VTPRIM).

(iii) Programs made available as a relocateable binary file using VTPRIM implicitly from the library; using the same loading procedure will simply use the new version.

Programs affected include VIEW, FONTS, a test program for STYLI, DOILY and demos like BOWLING, FRUITY, LIFE, Bouncing ball.

LT19 change

The display keyboard has now become LT1 and the second teletype is now LT0. (Note that under DOS, the second teletype must be plugged in at the mains as long as the PDP15 is being used, otherwise illegal interrupts will occur.) The device code change will affect:

(i) Programs which alter the .DAT slot table,

(ii) Device assignment statements, and

(iii) Commands in PIP.

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