-~
...
Magnetic Tape Unit
Card Reader
Card Punch
Printer
Chapter 2-AUTOMATIC DATA PROCESSING
RECORDING MEDIA
Magnetic Tape
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'.
' -'.' I','',1 •
eO-Column Cards
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eo- Column Cards
Paper Stock
INFORMATION TRANSFER
READ from tape ~
~ WRITE on tape
READ cards
~ PUNCH cords
Central Processor
Centrol Processor
-Central Processor
~ PR I NT documents
Centrol Processor
49.211X Figure 2-42.-0n-line peripheral equipment and recording media. '
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MACHINE ACCOUNTANT 3 & 2 computer system. Software consists of the
automatic programming techniques developed for the most efficient use of the hardware and is usually supplied by the manufacturer of particular systems.
Hardware.-Computer hardware falls into two categories, peripheral equipment and the central processor. PERIPHERAL EQUIPMENT includes all input and output devices associated with specific recording media such as, a card reader and punch with punched c21rds, or mag-netic tape units with magmag-netic tape. This peripheral equipment can operate ON-LINE, under direct control of the central processor (see fig. 2-42) or OFF-LINE, independently of the central processor. (See fig. 2-43.)
During on-line operations, data can be trans-ferred to and from peripheral devices and the central processor via CONTROL UNITS. These units may be free-standing, or built into either the central processor or the peripheral device, and receive their Signals or instructions from the stored program.
In off-line or AUXILIARY operations, the input and output devices are used in conjunction with other peripheral devices not directly con-nected to the system. Since input output data conversion operations are relatively slow com-pared to the speed of the central processing unit, off-line operations free the computer of time-consuming procedures and provide more time for the computing and processing of data by the central processor. For example, a system's output data could be written on mag-netic tape and in an off-line operation, con-verted to some other record form while the computer continues processing new data.
Software.-This consists primarily of gen-eral purpose programs that are common to many computer installations. Included among them would be assemblers and compilers which aid in producing machine language routines from a relative or nonmachine language source, plus sort, control, and other utility programs.
Card Oriented System
A system whereby information is fed into its input unit only by means of cards with its output also in the form of cards and/or printed reports, is commonly referred to as a CARD SYSTEM. These systems are usually relatively small, espeCially in their memory capacity and other storage facilities. Input data must be prearranged b.efore being fed into the system
42
but can remain in its memory unit until the programmed instructions call for its release, or replace it with new information.(See page 440) Tape Oriented System
Systems whose source of input data is from almost any medium, but essentially from per-forated paper or magnetic tape, are referred to as TAPE SYSTEMS. Because these systems are large and complex, they demand more processing ability, and therefore require faster input media than the much slower punched card input. In addition to larger memory capacities and other storage facilities, input and output devices may vary as to the type of media used and consist of several or many innumber.
Real Time Processing System
"How fast?" has been the factor of primary importance in computer operations. Recently, however, "How far?" has become Significant.
To move data from distant locations with the same relative speed with which it is processed is of growing importance, for where it is needed, is in many cases, far from where it originates.
To move data between locations around the country, computer information under the REAL TIME PROCESSING TECHNIQUE is now being transmitted over telephone, telegraph, and tele-type lines. These fast communication systems between a central computer and hundreds of remote pOints are eliminating the old problems of time and distance, which until now, had a direct bearing on computer applications. (See page 45.)
REAL TIME COMPU'IER SYSTEMS can store enormous masses of information and act upon any item within thousandths of a second.
Data is received and transmitted between loca-tions at remote pOints, and priorities are auto-matically assigned to different operations to ensure that action and response is in proportion to the urgency of the need. Through tne sys-tem's input devices, data is entered into the system and acted upon at the time of occur-rence. The need for original source documents is being eliminated, and due to its communica-tion facilities, centralized control of decentral-ized operations is now possible over areas of thousands of miles.
The scope of data processing performed by Machine Accountants has greatly expanded and become extremely diversified since the estab-lishment of our rating in 1948. Models and
Chapter 2-AUTOM'ATIC DATA PROCESSING
IBM 714 Card Reader IBM 759 Card Reader Control IBM 727 or IBM 729-1 Magnetic Tape Unit
IBM 727 or 729-1 Magnetic Tape Unit IBM 758 Card Punch Control IBM 722 Card Punch
IBM 727 or 729-1 Magnetic Tape Unit IBM 757 Printer Control IBM 717 Printer
IBM 727 or 729-IMagnetic Tape Unit IBM 760 Control and Storage IBM 720 or IBM 730 Printer
49.212X Figure 2-43.-0ff-line data conversion operations.
types of data processing equipment employed by the Navy today, vary in Size, dimension, and performance.
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You may at present be serving a tour of duty in an installation using some of the afore-mentioned machines and devices. Subsequent
MACHINE ACCOUNTANT 3 & 2