IBM Operating system software

The smaller S/360 models used Basic Operating System/360 (BOS/360), Tape Operating System (TOS/360), or Disk Operating System/360 (DOS/360, which evolved into DOS/VS, DOS/VSE, VSE/AF, VSE/SP, VSE/ESA, and then z/VSE).

The larger S/360 models used Operating System/360 (OS/360): Primary Control Program (PCP), Multiprogramming with a Fixed number of Tasks (MFT), which evolved into OS/VS1, and Multiprogramming with a Variable number of Tasks (MVT), which evolved into MVS. MVT took a long time to develop into a usable system, and the less ambitious MFT was widely used. PCP was used on intermediate machines; the final releases of OS/360 included only MFT and MVT.

When it announced the S/360-67 in August 1965, IBM also announced TSS/360 (Time-Sharing System) for delivery at the same time as the 67. TSS/360, a response to Multics, was an ambitious project that included many advanced features. It never worked properly, was delayed, canceled, reinstated, and finally canceled again in 1971. It was replaced by CP-67, MTS (Michigan Terminal System), TSO (Time Sharing Option for OS/360), or one of several other time-sharingsystems.

CP-67, the original virtual machine system, was also known as CP/CMS. CP/67 was developed outside the IBM mainstream at IBM's Cambridge Scientific Center, in cooperation with MIT researchers. CP/CMS eventually won wide acceptance, and led to the development of VM/370 (aka VM/CMS) and today's z/VM.

The S/360 Model 20 offered a simplified and rarely used tape-based system called TPS (Tape Processing System), and also DPS (Disk Processing System) that provided support for the 2311 disk drive. TPS could run on a machine with 8K of memory, and DPS required 12 K, which was pretty hefty for a Model 20. Many customers ran quite happily with 4 K and CPS (Card Processing System).

With TPS and DOS, the card reader was used (a) to define the stack of jobs to be run (Job Control Language), and (b) to feed in transaction data, like customer payments. But the operating system was held on tape or disk, and results (master files!) could also be stored on the tapes or hard drives. Stacked job processing became an exciting possibility for the small but adventurous computer user.

A little known and little used suite of 80 column punched-card utility programs known as Basic Programming Support (BPS) (jocularly: Barely Programming Support) was available for the S/360-30. It was a precursor of TOS on the Model 30.


IBM Data storage

In all tape formats, a tape drive (or "transport" or "deck") uses motors to wind the tape from one reel to another, passing tape heads to read, write or erase as it moves.

Magnetic tape was first used to record computer data in 1951 on the Eckert-Mauchly UNIVAC I. The recording medium was a thin strip of one half inch (12.65 mm) wide metal, consisting of nickel-plated bronze (called Vicalloy). Recording density was 128 characters per inch (198 micrometre/character) on eight tracks.

Small open reel of 9 track tape

Early IBM tape drives were floor-standing drives that used vacuum columns to physically buffer long U-shaped loops of tape. The two tape reels visibly fed tape through the columns, intermittently spinning the reels in rapid, unsynchronized bursts, resulting in visually striking action. Stock shots of such vacuum-column tape drives in motion were widely used to represent "the computer" in movies and television.

Quarter inch cartridges, a data format commonly used in the 1980s and 1990s.

Most modern magnetic tape systems use reels that are much smaller than the 10.5 inch open reels and are fixed inside a cartridge to protect the tape and facilitate handling. Many late 1970s and early 1980s home computers used Compact Cassettes encoded with the Kansas City standard. Modern cartridge formats include LTO, DLT, andDAT/DDC.

Tape remains a viable alternative to disk in some situations due to its lower cost per bit. This is a large advantage when dealing with large amounts of data. Though the areal density of tape is lower than for disk drives, the available surface area on a tape is far greater. The highest capacity tape media are generally on the same order as the largest available disk drives (about 5 TB in 2011). Tape has historically offered enough advantage in cost over disk storage to make it a viable product, particularly for backup, where media removability is necessary.

Tape has the benefit of a comparatively long duration during which the media can be guaranteed to retain the data stored on the media. Fifteen (15) to thirty (30) years of archival data storage is cited by manufacturers of modern data tape such as Linear Tape-Open media.

In 2002, Imation received a US$11.9 million grant from the U.S. National Institute of Standards and Technology for research into increasing the data capacity of magnetic tape.


IBM Magnetic tape

Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders. A device that stores computer data on magnetic tape is a tape drive (tape unit, streamer).

Magnetic tape revolutionized broadcast and recording. When all radio was live, it allowed programming to be prerecorded. At a time when gramophone recordswere recorded in one take, it allowed recordings in multiple parts, which mixed and edited with tolerable loss in quality. It is a key technology in early computer development, allowing unparalleled amounts of data to be mechanically created, stored for long periods, and to be rapidly accessed.

Today, other technologies can perform the functions of magnetic tape. In many cases these technologies are replacing tape. Despite this, innovation in the technology continues and tape is still widely used.

Over years, magnetic tape can suffer from deterioration called sticky-shed syndrome. Caused by absorption of moisture into the binder of the tape, it can render the tape unusable.

Audio recording

Magnetic tape was invented for recording sound by Fritz Pfleumer in 1928 in Germany, based on the invention of magnetic wire recording by Valdemar Poulsen in 1898. Pfleumer's invention used an iron(III) oxide(Fe2O3) powder coating on a long strip of paper. This invention was further developed by the German electronics company AEG, which manufactured the recording machines and BASF, which manufactured the tape. In 1933, working for AEG, Eduard Schuller developed the ring shaped tape head. Previous head designs were needle shaped and tended to shred the tape. An important discovery made in this period was the technique of AC biasing which improved the fidelity of the recorded audio signal by increasing the effective linearity of the recording medium.

Due to the escalating political tensions, and the outbreak of World War II, these developments were largely kept secret. Although the Allies knew from their monitoring of Nazi radio broadcasts that the Germans had some new form of recording technology, the nature was not discovered until the Allies acquired captured German recording equipment as they invaded Europe in the closing of the war. It was only after the war that Americans, particularly Jack Mullin,John Herbert Orr, and Richard H. Ranger were able to bring this technology out of Germany and develop it into commercially viable formats.

A wide variety of recorders and formats have developed since, most significantly reel-to-reel and Compact Cassette.

Video recording

The practice of recording and editing audio using magnetic tape rapidly established itself as an obvious improvement over previous methods. Many saw the potential of making the same improvements in recording television. Television ("video") signals are similar to audio signals. A major difference is that video signals use more bandwidth than audio signals. Existing audio tape recorders could not practically capture a video signal. Many set to work on resolving this problem. Jack Mullin (working for Bing Crosby) and the BBC both created crude working systems that involved moving the tape across a fixed tape head at very fast speeds. Neither system saw much use. It was the team at Ampex, led by Charles Ginsburg, that made the breakthrough of using a spinning recording head and normal tape speeds to achieve a very high head-to-tape speed that could record and reproduce the high bandwidth signals of video. The Ampex system was called Quadruplex and used 2-inch-wide (51 mm) tape, mounted on reels like audio tape, which wrote the signal in what is now called transverse scan.

Later improvements by other companies, particularly Sony, lead to the development of helical scan and the enclosure of the tape reels in an easy-to-handle cartridge. Nearly all modern videotape systems use helical scan and cartridges. Videocassette recorders are very common in homes and television production facilities though many functions of the VCR are being replaced. Since the advent of digital video and computerized video processing, optical disc media and digital video recorders can now perform the same role as videotape. These devices also offer improvements like random access to any scene in the recording and "live" time shifting and are likely to replace videotape in many situations.


IBM 1750, 2750 and 3750 Switching Systems

In 1969 IBM started marketing in five European countries the IBM 2750 Switching System – worldwide, the first stored-program-controlled PABX (Private Automatic Branch Exchange). Previously onlyelectromechanical Strowger and Crossbar PABXs were available.

The 2750 was sold in France, Germany, Italy, and Belgium. The other systems were sold in these countries and the United Kingdom. The Netherlands installed some in IBM sites.

The family of IBM 1750, 2750 and 3750 Switching Systems was developed from the IBM 1800 by the IBM La Gaude Research Laboratory near Nice, France for European markets only. Each system included twin stored-program controllers (each with some 600,000 lines of code, and nightly automatic switchover), twin disks, and solid-state switching. Extension, trunk and tie lines were connected by discrete transistors on plug-in panels.

SystemYear first marketedExtensionsTrunks + tie linesOperator desks
IBM 2750 Switching System1968100-500?
IBM 3750 Switching System1970250-2200?300 Max?
IBM 1750 Switching System1979100 - 7600 - 961 - 5

The systems all had both voice and data functions – the marketplace largely bought them for their then-new voice and management functions. Early-1960s computers had hardly any typewriter-like terminals and no screens – the IBM Switching Systems introduced the novelty of simple data capture from touch-tone telephones.


IBM products

The following is a list of products, some notable, some less so, from the International Business Machines (IBM) Corporation and its predecessor corporations, beginning in the 1890s, and spanningpunched card equipment, time clocks, and typewriters, via mainframe computers and minicomputers, to microprocessors, software, and more.

This list is eclectic; it includes, for example, the AN/FSQ-7, which was not a product in the sense of offered for sale, but was a product in the sense of manufactured - produced by the labor of IBM. Also missing are RPQs, OEM products (semiconductors, for example), supplies (punched cards, for example). That products are missing is not by fiat, but simply because no one has added them.

IBM sometimes used the same number for a system and for the principal component of that system. For example, the IBM 604 Calculating Unit is a component of the IBM 604 Calculating Punch.

Keypunches, verifiers, and derived machines

Sorters, Statistical, and derived machines


[edit]Reproducing Punch, Summary Punch, Gang Punch, and derived machines


[edit]Tabulators, Accounting machines

[edit]Calculating devices

Other Unit Record Equipment