To describe the advantages and disadvantages of using the new system - the documentation provided, and the method used in generating a new system.
DOS V2A has been implemented on the PDP15 as from 30 August 1972. The major disadvantages of the system is that blank common in Fortran is called XX again.
Advantages are:-
(1) Full documentation is available by the PDP15 in two binders entitled: 'Software Performance Summary and Software News' and 'DOS System Description'.
(2) DUMP, DTCOPY, FOCAL, and EDITVT are now on the system, and more filespace is now available. To achieve this a number of handlers have been deleted from the system. If anyone wants them back please ask, it should be quite straightforward to replace them. Our own copies of MTA and MTF are on the system.
(3) Instructions for running DOSSAV are in the Software Performance Summary (SPS).
(4) There is a new command in Chain to force COMMON areas to stay within bank boundaries - see SPS.
(5) Data Directed I/0 of arrays held in COMMON gives wrong results.
(6) Loader makes repeated passes through: .LIBR, .LIBR5 and <IOS> to resolve .CLOBLs. There should now be no problem with backward references in .LIHR5.
(7) New switches in Macro - see SPS.
(8) Update can now copy out a single file from a library - see SPS.
(9) There is a description of the display keyboard handler (LKA) in SPS.
(10) Fortran can now output double line spacing and overprinting to the teletype.
NB. There is no writeup anywhere of EDITVT, With VTON in Monitor saying TV ON in EDITVT allows files to be displayed on the screen. When a LOCATE or FIND is done the file is displayed up to and including the line found or located. TOP and CLOSE makes the screen blank. All command requests are on the teletype - and PRINT causes output both to the screen and teletype. Lines input with the Editor in INPUT mode appear character by character on the screen.
NB. Also - Anyone using more than 300 (octal) blocks of disk is being antisocial.
Load the new system using DOSSAV, having saved the old one. Log in under MI CLOG SYS,
Then use SGEN to generate a paged system and to delete the system programs that we don't need, such as SRCCOM and TKB. Don't change I/0 devices yet.
Then using PIP transfer our device handlers (PFA., LTA., ICA., MTA. and MIT.) from Dectape 2/4 to user IOS. The system won't let you login as IOS, so stay in SYS. We need our own MTA. and MTF. as we want the default density of writing to tape to be 556 bpi. Create the UICs for the systems users by commands like:-
N DK <FRA>
Cal1 SCEN again and change the I/O Devices - remove those we don't want such as: Disk Pack (DP), Line Printer (LP), Storage tube (VF) and card reader (CD). Add our own devices - the skips required are in my DOS SGEN file. This will delete handlers that we don't need.
Use Update to introduce VTPRIM, LTORPB, TRACK and TABLET into LIBR. Up to date versions of these are on Dectape 24.
Lastly use PIP to delete all files belonging to user PER.
There is a listing of the .LIBR file and the default .DAT slots on the notice board by the PDP15.