Hardware manual

Fixed a bug in the file date code; introduced another bug in the same code.
Version 14/5 -- March 1, 1978
Additions: ReadCalendar and SetCalendar - analogus to DayTime and SetDaytime only they conform to
the new time standard. DayTime and SetDaytime will continue work correctly until April 30, 1978. A new
declaration file, AltoDefs.d was created; some things were moved there from SysDefs.d. Definitions of the
format of .BB (overlay), and .Syms files were added to SysDefs.d. This OS has room for a ’big’ bittable - a
special OS version is not required.
Deletions: The system log was de-implemented. LogOpen, LogClose, and MakeLogEntry are now Noops.
They will be removed when an incompatible OS is next released.
Reorganizations: Noop, TruePredicate and FalsePredicate were moved from StreamsML.asm to
BFSML.asm (up a few Junta levels). Fast streams were split out of disk streams: FastStreamsB.bcpl and
FastSteamsA.asm. Streams.bcpl was split into 3 files: DiskStreams.bcpl, DiskStreamsMain.bcpl, and
DiskStreamsAux.bcpl; StreamsML.asm disappeared.
Changes: A bug in ReturnFrom was fixed (this only matters if you use the microcode version of the frame
allocator). TruePredicate now returns -1 (it used to return 1). If the unrecoverable disk error routine in the
BFS returns, the cleanup procedure is called and things plunge on. OpenFile with a filename containing a
non-existant directory now returns 0 instead of calling Swat. The Diablo printer bits (0-7) are now ignored
by the keyboard interrupt routine.
Version 13/5 -- May 16, 1977
Additions: ParseFileName (a lower level directory function) was made available to users.
Changes: Minor, yea insignificant bugs fixed.
Version 12/5 -- March 20, 1977
Additions: ClockSecond. Location 613b is now reserved to indicate to RAM microcode what sort of Alto
we are on: 0 implies Alto I; -1 implies Alto II.
Changes: Time-keeping accuracy improved slightly. BFS is now reentrant--you may have several
independent disk activities going concurrently (this will make CopyDisk more reliable).
Version 11/5 -- January 9, 1977
Additions: eventInLd and eventCallSubsys processing added. Also now possible to install the operating
system with logging disabled.
Changes: Booting process somewhat more robust. Several changes to improve diagnostic information
about parity errors provided by Swat. Improved password protection. Alto II fixes in parity and timer
routines.
Version 10/5 -- November 2, 1976
Changes: A nasty bug in the disk routines was uncovered and fixed. It was responsible for occasionally
garbaged files.
Version 9/5 -- September 25, 1976
Additions: verNewAlways option to OpenFile; changeSerial entry on file leader pages.
Changes: Various bugs relating to keeping file version numbers were fixed.
Version 8/5 -- August 28, 1976
Alto Operating System May 5, 1980 35
For Xerox Internal Use Only -- December 15, 1980