SECTION IV
HARDWARE CONFIGURATION COMMANDS
When a Time Shared Basic (TSB) System is first loaded into the computer, the
software assumes that the minimum hardware configuration exists. That is,
the multiplexor must be in I/O channel 10, the operator console is 11, the
Time Base Generator in 12, the photoreader in 13, and the initial disc
unit (named disc-0) in 14 and 15. This configuration can be expanded on-
line without restarting the TSB System from scratch.
For example, a magnetic tape unit can be added or moved from one channel to
another, or a supplemental disc storage unit can be added. If Data Phone
connections are desired, a Data Set Disconnect I/O Board is required. Only
the minimum hardware configuration outlined above cannot be altered with
hardware configuration commands.
The operator notifies the TSB System of changes to the hardware by means of
various commands: MAGTAPE, DISC, PHONES, LOCK and UNLOCK. The TSB System
has no means of checking on the validity of the I/O channels specified. If
used improperly, these commands can cause TSB System failure, thus they
should only be used with extreme care.
If the operator specifies an incorrect disc I/O channel, the first attempt
to write on that disc will cause a TSB System failure. Or, if the magnetic
tape is introduced incorrectly, the TSB System will be unable to complete
the SLEEP operation, as it will attempt indefinitely to dump onto a non-
existent magnetic tape.
The hardware commands are the only exception to the decimal numbering
employed in the TSB System. The select codes (I/O) channels) specified as
parameters in these commands are octal (base eight) numbers. All other
numbers, including disc track numbers are decimal (base ten).
MAGTAPE
A Hewlett-Packard 3030 or 7970 Magnetic Tape unit may be added
to the hardware as an option. Once the TSB System is aware of
the magnetic tape, a copy of the software will be dumped whenever
a SLEEP Command is execution. This copy can be reloaded if the
TSB System is destroyed in core.
The format for MAGTAPE Command is as follows:
MAGTAPE-sc
MAGTAPE-sc*
where sc is the high priority (lower numbered) select code (I/O
Channel) in octal of the magnetic tape unit. A select code of
zero tells the TSB System that the magnetic tape unit has been
removed. An asterisk indicates that an HP 18131 magnetic tape
unit interface board is used (7970 controller).
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DISC
Up to 256 tracks of 90 to 128 sectors each may be defined in the
TSB System. The 256 tracks are allocated into four logical discs
of 64 tracks each, numbered from 0 to 3. A physical disc unit of
128 tracks would be defined for the TSB System as two logical discs
of 64 tracks each, 96 (drum) as 64 and 32, and 192 (drum) as three
64 tracks discs. A drum of 48 tracks must be defined as a disc of
64 tracks with tracks 48 to 63 locked. Disc units of less
than six megabits (64 tracks) are not allowed.
The DISC Command is used to inform the TSB System that a new disc
has been added or an old disc removed. Since disc-0 is always as-
sumed to reside in I/O channels 14 and 15, only 1 through 3 can
be parameters in the DISC Command. DISC Commands are also accept-
ed by the TSB Loader. (See Section VII.)
The format of the DISC Command is as follows:
DISC-disc number, select code, track length
where select code is an octal number indicating the high priority
I/O channel of disc, disc no. is a number from 1 to 3 indicat-
ing the disc logical number, and track length is a decimal number
from 90 to 128 indicating the number of sectors per track.
If the select code is 0, the specified disc will be removed from
the TSB System. This will be allowed only if all tracks on the
disc have been previously LOCKed. (see this section). It is neces-
sary to remove a disc this way if the track length or select code
is to be changed.
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For the drum, logical track n refers to physical track 4n through 4n + 3.
(For example, logical track 0 is physical tracks 0 to 3, and 1 is 4 to 7.)
When a disc has more than 64 logical tracks and is used as more than one
logical disc, the order of entering DISC commands will determine the rela-
tion of disc numbers to disc tracks. Each DISC command will assign the
lowest available block of 64 tracks to the disc number specified in the
command. For example, the following commands are entered:
DISC-1,14,90
DISC-2,16,128
DISC-3,16,128
DISC-3,16,32,63
where channels 14-15 contain a 128 track disc and channels 16-17 contain a
96 track drum, then disc-0 refers to tracks 0-63 of the disc, disc-1 refers
to tracks 63-127 of the disc, disc-2 refers to tracks 0-63 of the drum, and
disc-3 refers to tracks 64-95 of the drum.
If the system contained only a 192 track drum, it would be defined as three
discs of 64 tracks each:
DISC-1,14,128
DISC-2,14,128
PHONES
When an Auto Disconnect I/O Board (HP 12584A-02) is connected
to the hardware for controlling user telephone connections,
the PHONES Command indicates to the TSB System the channel of
the board and, optionally, the number of seconds allowed the
user to log on through a Data Set.
PHONES-sc [,n]
where sc is the select code (I/O channel) of the Auto Discon-
nect I/O Board, and n, if included, specifies the number of
seconds (<= 323) given the user to log on before the TSB System
will hang up his telephone. If n is not specified, 120 seconds
is assumed; however, n must not be greater than 323. An sc
equal to zero indicates the removal of the board.
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A user telephone line is automatically disconnected when the connection
is broken for two or more seconds.
LOCK
The LOCK Command allows the operator to make certain
disc tracks unavailable to the TSB System. The format
of the LOCK Command is as follows:
LOCK-n,track[,track]
where n is the disc logical number (0 through 3) and
track is a decimal quantity specifying a track on that
disc (0 through 63). If only one track is specified,
just that one track will be locked. If two track para-
meters are given, they determine the first and last
tracks to be locked.
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If a LOCK Command specifies an area containing user programs, these
will be lost. If the area contains TSB System tables, the command
will be rejected. TSB System tables cannot be removed without de-
stroying the TSB System.
The LOCK Command can be used to replace a disc in the TSB System, by
locking all the tracks of the disc. When the new disc is installed,
the tracks can be unlocked. The LOCK Command is also used to elim-
inate tracks that are believed to be physically faulty.
Discs which to not have exactly 64 tracks can be used by LOCKing
those tracks which do not physically exist (i.e., locking tracks
32-63 of the second logical disc of a 96 track drum).
UNLOCK
The function of the UNLOCK Command is the opposite of
the LOCK Command. The operation makes the specified
tracks available to the TSB System. The format is
identical to that for LOCK:
UNLOCK-n,track[,track]
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Examples:
Command Action
LOCK-3,5,23 Locks disc-3 tracks 5 through 23 inclusive.
UNLOCK-3,5,10 Unlocks disc-3 tracks 5 through 10 inclusive.
UNLOCK-3,11,23 Unlocks disc-3 tracks 11 through 23 inclusive.