The following is the text of an IBM press fact sheet distributed on September 14, 1956.

The 650 to date

The central element of the new IBM 650 RAMAC is the 650 Magnetic Drum Data Processing Machine. The basic 650 is a medium sized computer. The first machine was installed in late 1954 and since then over 350 have been placed in operation in this country and abroad. They are handling both commercial and scientific applications in nearly every type of business and industry. The 650 is manufactured at IBM's Endicott, N. Y. plant. There are about 1,000 IBM 650's of all types now on order, and they are coming off the production line at the rate of more than one a day. It is far ahead of all competition.

The 650 is a stored program data processing machine. It has the ability to store internally both data processing instructions -- called the program -- and the data to be processed. The basic 650, which rents for $3,750 a month, is a punched card operated machine with a magnetic drum memory that will store 20,000 digits. But 650 systems are now available with a great variety of input, output, and storage devices. The system may be magnetic tape operated. Up to 6 IBM 727 magnetic tape units may be connected to the basic computer through a 600-digit, high-speed magnetic core memory IBM 653 storage unit. Also, an IBM 407 accounting machine may be connected to the system to give it a printer output.

The memory

The latest addition to the 650 is the IBM 355 random access memory a storage medium in which any group of data may be reached quickly and directly, without search.

Up to four 355 memory units may be connected to the 650 system. A 355 is a stack of 50 metal disks, each two feet in diameter. Both sides of the metal disks are treated so that 100 disk faces are available for storage. On each disk face there are 100 concentric data tracks. Six-hundred digits of recorded data may be stored in each track. In other words, each track holds 60 words with signs.

Each 355 unit has a capacity for 6,000,000 digits. With the maximum of four units, the 650 can have available, therefore, 24,000,000 digits stored in a random access memory. This is the equivalent to a file of records stored on 300,000 punched cards.

To process file data, the information stored in the memory is read from and written into the data tracks on the magnetic disks by access arms. The magnetic disks in each unit continuously rotate past three independent access arms at 1200 RPM, and each arm can move to any data track.

The access arms move under instructions stored in the 650. A seek instruction sends an arm to the addressed data track. A read instruction causes the access arm to read the addressed data track into immediate access storage (the IBM 653 magnetic core memory). A write instruction causes the arm to write into the addressed data track the information that is in immediate access storage.

Interrogation of 650 RAMAC

Another feature of the 650 RAMAC important to "in-line" processing is the facility for quick communication with the system, with minimum interference with the routine operating procedure, to inquire into the status of records or to enter new information. This is done through the IBM 838 Inquiry Station. The 838 uses a modified IBM electric typewriter from which inquiries and data can be sent to the 650 and to which the 650 can send replies. Ten inquiry stations are available for each 650 RAMAC system. Each is connected to the system by a cable 50 feet in length and the ten available stations, connected in series, provide a maximum of 500 feet from an inquiry station to the 650 machine area.

The inquiry or information to be sent to the 650 is typed on a form at the inquiry station at the same time that it is transmitted to the processing unit. The 650 stored programming processes the inquiry and transmits the reply back to the inquiry station where it is typed on the form. Complete flexibility and positive control of inquiry station operation is provided by a plastic program tape at each station operating in conjunction with the 650 stored program. The program tape also provides flexibility in the format of the printed document at the inquiry station.

Applications of 650 RAMAC

A good general area for 650 RAMAC application is billing and inventory control, particularly in those instances -- owing to the presence of the 650 -- where high level computation is involved. Continuous, in-line processing means that decisions, such as whether or not to extend credit or to make substitutions, can be made in time to be effective. There is closer, more effective control over inventory. Back ordering is reduced, improving the service to customers. Continuous, in-line processing makes possible a continuous flow of orders through the warehouse, resulting in smoother operation, better service to customers. Also, there is immediate access to the file records (inventory records, customer files).

Another good area in which to illustrate the advantages of 650 RAMAC is piecework payroll and costs. With continuous, in-line processing, cost figures are continually up to date. Employee earnings are continually up to date; terminations are easily handled. All sorting of detail entries is eliminated. More comprehensive cost breakdown can be accommodated. Cost records are stored internally as part of the production scheduling file; payroll is integrated with production scheduling. Integration of these related applications results in economy.