Programming instructions

from the Light Pen, the computer carries out previously programmed
instructions. Requires Real-Time Option.
THE 18-BIT RELAY BUFFER, TYPE 67-4, provides contacts which
operate devices of higher power rating. The relays have form “D”
contacts, which open and close in approximately 3 milliseconds.
Requires Real-Time Option.
THE PROGRAMMED MAGNETIC TAPE CONTROL, TYPE 54, controls
up to four Magnetic Tape Transports, Type 50. Information is read
from or written on the tape. The format on the tape may be pro-
grammed to be compatible with IBM tapes having a density of 200,
6 + 1 bit characters per inch. Requires Real-Time Option.
THE MAGNETIC TAPE TRANSPORTS, TYPE 50, are used with the
Programmed Magnetic Tape Control, Type 54.
THE AUTOMATIC LINE PRINTER AND CONTROL, TYPE 62, operates
at up to 600 lines per minute, 120 columns per line. Each column
may print one of 64 characters. Spacing format is controlled by a
punched format tape in the Printer. Once a command to print or space
is given, the Internal Processor is not required. Approximately one
per cent of program running time is required to operate the Line
Printer at a 600~line-per-minute rate. Requires Real-Time Option.
THE CARD READER AND CONTROL, TYPE 41-4, operates at a rate of
up to 200cards per minute. Cards are read column by column. Column
information may be read in alpha-numeric or binary mode. The alpha-
numeric mode converts the 12-bit Hollerith Code of one column into
the six-bit binary-coded decimal code with code validity checking.
The binary mode reads a 12-bit column directly into the PDP-4. Ap-
proximately one per cent of a Card Reader program running time is
required to read the 80 columns of information at the 200 cards per
minute rate. Requires Real-Time Option.
THE CARD PUNCH CONTROL, TYPE 40-4, enables the operation of a
standard IBM Type 523 Summary Punch with PDP-4. Cards are
punched row by row at a rate of 100 cards per minute. Approximately
0.3 per cent of program running time is required to operate the Card
Punch at the lOO-card-per-minute rate. Requires Real-Time Option.
PROGRAMMING AIDS
Several programs are supplied with each PDP-4 to assist the programmer
in routine tasks. They include: The PDP-4 Assembly Program, the DDT-14
debugging tape, double-precision floating point routines,
routines, a tape reproducer, punch routines, an octal
an algebraic compiler, and a floating point functions
enable various functions, such as double precision floating-point sine,
be computed. See Appendix 6.
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