Data Synchronizer - IBM 709 General Information Manual

IBM 727 or 729-1 Magnetic Tape Unit
Figure 65. Tape-to-717 Printer
IBM 757 Printer Control
4. Tape-to-High Speed Printer (Figure 66)
The
IBM
720 or 730 Printer (Model 2),
IBM
727
or 729 I Magnetic Tape Unit, and the
IBM
760 Con-
trol and Storage may perform independent tape-to-
printer operations. Information can be read from
magnetic tape and printed in the form it appeared on
tape. The tape can be recorded either on card-to-tape
equipment or on one of the
IBM
data processing sys-
tems. Auxiliary high-speed printing from tape does
the following:
a. It converts magnetic tape records to printed form
without depending upon computer operations.
b. It prints 500 lines per minute with the 720, or
1,000 lines per minute with the 730 Printer_
c. It uses 120 printing positions of 47 characters
each. Alphabetic, numerical, and special sym-
bols can be printed.
d. It checks information automatically.
5. Auxiliary Operations with
IBM
1401
An
IBM
1401 Data Processing System can be used for
all auxiliary operations. This system consists of a
1401 Processing Unit with as many as 16,000 positions
of core storage, a 1402 Card Read Punch, 1403 Printer,
and six Magnetic Tape Units (either 729 II or 729
IBM 717 Printer
IV). The 1401 is particularly adapted to such conver-
sion operations as:
(1)
card-to-tape, with off-line
audit, control, and edit of input data at 800 cards per
minute; (2) tape-to-card, at 250 cards per minute; (3)
tape-to-printer, at 600 lines per minute.
Data Synchronizer
In most computers, internal processing speeds are
much faster than the input devices that read data or
the output devices that record the results. For ex-
ample, the internal speed of the 709 is approximately
34 times faster than that of the 729 I tape unit and
833 times faster than that of the card reader_ How-
ever, a word is not always available from tape every
34 machine cycles. Because magnetic tape is a plastic
medium being read by a mechanical device, the data
transmission rate varies. Actually, input-output de-
vices are asynchronous with the computer; that is,
no fixed time relation exists between these devices
and the computer_
Some systems overcome this problem by suspending
all computing while an
1-0
device is being used. The
core storage waits until the input device has accumu-
lated a data word; this word is stored; the computer
then waits for the next piece of data_ The stored
IBM 727 or 729-1 Magnetic Tape Unit
Figure 66. Tape-to-720 or 730 Printer
IBM 760 Control and Storage IBM 720 or IBM 730 Printer
Input-Output Components 31