The following is the text of an undated IBM Data Processing Division press technical fact sheet. It probably was distributed in 1959.
The IBM RAMAC 650 electronic data processing system combines the capabilities of the world's most widely-used computer with the flexibility of random-sequence data availability. Two basic elements make up the RAMAC 650- --an IBM 650 data processing system and an IBM 355 magnetic disk memory file.
The basic 650 is a stored program, magnetic drum computer with logical ability. It remembers instructions and follows them as the need arises during the solution of a problem. Routine or complex calculations are solved with equal facility in accounting and technical applications. More 650's are in use today than any other type of computer. The system may be expanded, building-block fashion, when growing business volume creates a need for greater capacity and speed.
Linked to the 650 is the IBM 355 memory disk file. The ability of this RAMAC unit to handle transactions quickly regardless of sequence and to locate information instantly without searching through large volumes of data is the basis of its name -- a Random Access Method of Accounting and Control. It permits single-step processing in which every record affected by a transaction is updated automatically in the same procedure.
In combination, the two elements of this electronic data processing system enable management to obtain information regarding the status of any account, as of that moment. The net effect is to narrow the critical gaps between business problems, collection of facts, decisions and the actions taken on the basis of those factors.
The productivity of the IBM RAMAC 650 may be expanded with the use of magnetic tape units to provide concentrated storage of great volumes of information for high-speed reading and writing. Incorporation of the tape units creates an IBM RAMAC 650 Tape system.
Further flexibility is provided in IBM RAMAC 650 systems with the addition of a number of variations to the basic components:
- Immediate access storage added to the 650 increases data processing speed greatly by transferring blocks of information from other parts of the system to a core storage unit in a single operation. The information then may be referred to factor-by-factor with reference speeds that virtually are instantaneous.
- Standard punched-card output of information from the 650 may be supplemented by the addition of an IBM 407 accounting machine which provides printed reports.
- Random access memory is expanded with the use of double capacity memory disks. Each basic RAMAC memory disk file contains six million information digits. Alphabetic characters are represented by two digits and numeric characters by one digit, so that groups of digits compose words or numbers. Double capacity places 12 million digits of memory storage in each disk file. Up to four RAMAC memory units may be used in a RAMAC 650 system, giving it a random access memory of as many as 48 million digits.
- Remote-site control is available through inquiry stations on which requests for specific information, such as the inventory position of an item, may be typed. Responses are typed automatically on an inquiry station output typewriter.
- Direct, high-speed entry of information into the 650 with punched paper tape is available. This makes possible rapid, effortless processing of information accumulated in integrated data processing systems which use paper tape as their common language medium.
IBM RAMAC 650 console
The console is the heart of the 650 system. In it is a magnetic drum memory unit in the form of a cobalt-nickel plated metal cylinder which revolves at 12,500 RPM. Available in two models, the memory drum has a storage capacity of either 20,000 or 40,000 digits of information. To solve a problem or process information a set of instructions -- the program -- is designed and stored on the drum.
These instructions are read by the machine in sequence and input information is stored and processed as directed by that sequence. The average access time to data or instructions on the magnetic drum memory is 2.4 milliseconds -- 2.4 thousandths of a second.
IBM RAMAC 650 input and output
Information is entered into and taken from the data processing system in punched card form through IBM 533 and 537 card read punch units, the 543 input card reader and 544 output card punch. The 533 has two card feeds. One reads input data and instructions at up to 200 cards a minute; the other punches out results in new cards at up to 100 cards a minute. The 537 has one feed through which cards are read and processed; output results are punched into the same cards. It handles cards at the rate of up to 155 a minute, reducing card costs and usually increasing punching speed. The 543 and 544 operate at speeds up to 250 cards a minute to provide faster input and output and increased versatility.
Printed output is obtained by linking a modified IBM 407 accounting machine to the system. It is able to list information, send data into the RAMAC 650 system for processing and accept results from the system for printing, storing or accumulating. Use of the 407 control panel adds operating flexibility to the overall system. The two card read punch machines, the card reader, the card punch and the accounting machine may be used in this system in any combination of up to three units.
IBM RAMAC 650 memory
Three types of memory storage, in addition to the program storage in the console, are available in the RAMAC 650 system:
- Immediate access memory storage. The IBM 653 magnetic core storage unit reduces processing time in the system. Blocks of information are transferred into it from other components of the machine so that a problem can be worked on from the core storage, rather than the magnetic drum. Information in high-speed core storage is available instantaneously. The unit has a capacity of 600 digits. Transfer of information into and out of the core storage unit is accomplished in a negligible amount of time.
- Random access memory storage. With the IBM 355 magnetic disk memory unit, the RAMAC 650 system is able to go directly to a specific piece of information without searching for it through all the other stored data. Individual business transactions are processed immediately as they occur, without batching.
- Information is stored magnetically on a stack of 50 disks which rotate continuously at 1,200 RPM. Each metal disk is two feet in diameter and is coated on each side with a magnetic material. The face of a standard disk contains 100 tracks, in each of which 600 digits may be stored. In double capacity disk files there are 200 information tracks on each disk face. Thus, standard memory file capacity is six million digits and the double capacity Model 2 IBM 355 disk storage unit can store 12 million digits. Up to four random access memory units may be used in a RAMAC 650 system.
- In each memory file there are three electronically-controlled access arms containing magnetic heads. They read and write the information contained on the rotating disks. They act independently of each other, but each arm can be directed to any track in the file. As a result, there can be simultaneous seeking of three different records and information constantly is available for processing.
- Instructions are given to the three access arms from the IBM 650 console. A "seek" instruction sends an arm to the desired data track. A "read" instruction brings data from the disk, through an access arm, into the system's immediate access storage unit. A "write" instruction results in the recording on the disk of information which has been in immediate access storage.
- Magnetic Tape Memory Storage. The RAMAC 650 system may include storage of information on magnetic tape. As many as six IBM 727 magnetic tape units may be used. Two hundred characters are stored on each inch of the half-inch-wide tape. Information then may be read from or written on the tape in blocks of 60 ten-digit words at the rate of 75 inches a second. Up to 23,000 ten-word records or 7,600 sixty-word records can be placed on one 2,400-foot-long reel of tape.
- Tape usage is valuable particularly when growing volumes of information create a need for greater processing speeds. As input and output adjuncts to the RAMAC 650 system, the magnetic tape units permit vast files of data to be condensed into small reels. Increased speed thus is supplemented by file storage and handling economy.
- Historical data -- personnel and payroll records, customer and production information -- often is recorded on magnetic tape when it will be subject to repetitive use. As the tape is processed, current activity in punched card form is combined with the tape data. An updated output tape is written during the process to serve as the input tape for subsequent processing.
- Information stored on magnetic tape also can be processed against information stored on random access magnetic disks for the automatic preparation on the 407 accounting machine of reports involving data from both sources.
RAMAC 650 remote control
Requests for specific information, such as the inventory position of an item, may be made of the RAMAC 650 system from IBM 838 inquiry stations. The request is entered on a typewriter keyboard, information is located immediately in the RAMAC memory disk file and the answer is typed out at the inquiry station.
As many as 10 inquiry stations can be used in a RAMAC 650 system. They can be placed at a data source, such as the receiving department, so that inventory records can be updated without delay. A cable 50 feet long is supplied with each inquiry station to link it to the machine. The stations can be linked in series to place the furthermost station 500 feet from the RAMAC 650 location. Individual cables of much greater length are available on request.