IBM 727

Last updated
An IBM 704 mainframe with IBM 727 tape drives on the left. (image courtesy of LLNL) IBM 704 mainframe.gif
An IBM 704 mainframe with IBM 727 tape drives on the left. (image courtesy of LLNL)
Half-inch tape reel with write protect rings Write protect ring.agr.jpg
Half-inch tape reel with write protect rings
Model of an IBM 7272 tape drive Model of IBM 727 Tape Drive (7100678957).jpg
Model of an IBM 7272 tape drive

The IBM 727 Magnetic Tape Unit was announced for the IBM 701 and IBM 702 on September 25, 1953. It became IBM's standard tape drive for their early vacuum-tube era computer systems. Later vacuum-tube machines and first-generation transistor computers used the IBM 729-series tape drive. The 727 was withdrawn on May 12, 1971. [1]

The tape had seven parallel tracks – six for data and one to maintain parity. Tapes with character data (BCD) were recorded in even parity. Binary tapes used odd parity. Aluminum strips were glued several feet from the ends of the tape to serve as logical beginning and end of tape markers. Write protection was provided by a removable plastic ring in the back of the tape reel.

tracks6 data, 1 parity
chars/inch200 characters/inch
Tape speed75 inches/second
Rewind speed500 inches/second (average)
Transfer rate15,000 characters/second
Start time5 milliseconds
Stop time5 milliseconds
Width of tape1/2 inches
Length of reel2,400 feet
Composition PET film (Mylar) or cellulose acetate base

Related Research Articles

<span class="mw-page-title-main">Tape drive</span> Data storage device

A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic-tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and a long archival stability.

<span class="mw-page-title-main">IBM 704</span> Vacuum-tube computer system

The IBM 704 is a large digital mainframe computer introduced by IBM in 1954. It was the first mass-produced computer with hardware for floating-point arithmetic. The IBM 704 Manual of operation states:

The type 704 Electronic Data-Processing Machine is a large-scale, high-speed electronic calculator controlled by an internally stored program of the single address type.

<span class="mw-page-title-main">IBM 650</span> Vacuum tube computer system

The IBM 650 Magnetic Drum Data-Processing Machine is an early digital computer produced by IBM in the mid-1950s. It was the first mass produced computer in the world. Almost 2,000 systems were produced, the last in 1962, and it was the first computer to make a meaningful profit. The first one was installed in late 1954 and it was the most-popular computer of the 1950s.

<span class="mw-page-title-main">IBM 701</span> Vacuum-tube computer system

The IBM 701 Electronic Data Processing Machine, known as the Defense Calculator while in development, was IBM’s first commercial scientific computer and its first series production mainframe computer, which was announced to the public on May 21, 1952. It was invented and developed by Jerrier Haddad and Nathaniel Rochester based on the IAS machine at Princeton.

<span class="mw-page-title-main">IBM 709</span> Vacuum tube computer system

The IBM 709 was a computer system, initially announced by IBM in January 1957 and first installed during August 1958. The 709 was an improved version of its predecessor, the IBM 704, and was the third of the IBM 700/7000 series of scientific computers. The improvements included overlapped input/output, indirect addressing, and three "convert" instructions which provided support for decimal arithmetic, leading zero suppression, and several other operations. The 709 had 32,768 words of 36-bit magnetic core memory and could execute 42,000 add or subtract instructions per second. It could multiply two 36-bit integers at a rate of 5000 per second.

<span class="mw-page-title-main">IBM 700/7000 series</span> Mainframe computer systems made by IBM through the 1950s and early 1960s

The IBM 700/7000 series is a series of large-scale (mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use vacuum-tube logic and were made obsolete by the introduction of the transistorized 7000s. The 7000s, in turn, were eventually replaced with System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with OS/360 and the high cost of converting software kept many 7000s in service for years afterward.

<span class="mw-page-title-main">IBM 305 RAMAC</span> First computer to use magnetic disk storage

The IBM 305 RAMAC was the first commercial computer that used a moving-head hard disk drive for secondary storage. The system was publicly announced on September 14, 1956, with test units already installed at the U.S. Navy and at private corporations. RAMAC stood for "Random Access Method of Accounting and Control", as its design was motivated by the need for real-time accounting in business.

<span class="mw-page-title-main">IBM 729</span>

The IBM 729 Magnetic Tape Unit was IBM's iconic tape mass storage system from the late 1950s through the mid-1960s. Part of the IBM 7-track family of tape units, it was used on late 700, most 7000 and many 1400 series computers. Like its predecessor, the IBM 727 and many successors, the 729 used 12 inch (13 mm) magnetic tape up to 2,400 feet (730 m) long wound on reels up to 10+12 inches (270 mm) diameter. To allow rapid tape acceleration, long vacuum columns were placed between the tape reels and the read/write heads to absorb sudden increases in tape tension which would otherwise break the tape. Write protection was provided by a removable plastic ring in the back of the tape reel.

The UNISERVO tape drive was the primary I/O device on the UNIVAC I computer. It was the first tape drive for a commercially sold computer.

<span class="mw-page-title-main">IBM 702</span> Vacuum tube computer system

The IBM 702 was an early generation tube-based digital computer produced by IBM in the early to mid-1950s. It was the company's response to Remington Rand's UNIVAC—the first mainframe computer to use magnetic tapes. As these machines were aimed at the business market, they lacked the leading-edge computational power of the IBM 701 and ERA 1103, which were favored for scientific computing, weather forecasting, the aircraft industry, and the military and intelligence communities.

The MANIAC II was a first-generation electronic computer, built in 1957 for use at Los Alamos Scientific Laboratory.

The Massbus is a high-performance computer input/output bus designed in the 1970s by Digital Equipment Corporation (DEC). The architecture development was sponsored by Gordon Bell and John Levy was the principal architect.

The IBM 726 was IBM's first magnetic tape unit. It was a dual magnetic tape reader/recorder developed for use with the IBM 701 and announced on May 21, 1952. This model of tape unit was shipped with the IBM 701 from December 20, 1952 until February 28, 1955. Unlike later IBM 7 track drives, the 726 could read backwards as well as forwards.

<span class="mw-page-title-main">IBM 7-track</span> Magnetic tape format introduced by IBM in 1952

IBM's first magnetic-tape data storage devices, introduced in 1952, use what is now generally known as 7-track tape. The magnetic tape is 12 inch (13 mm) wide, and there are six data tracks plus one parity track for a total of seven parallel tracks that span the length of the tape. Data is stored as six-bit characters, with each bit of the character and the additional parity bit stored in a different track.

<span class="mw-page-title-main">9-track tape</span> Magnetic tape format introduced by IBM in 1964

9-track tape is a format for magnetic-tape data storage, introduced with the IBM System/360 in 1964. The 12 inch (12.7 mm) wide magnetic tape media and reels have the same size as the earlier IBM 7-track format it replaced, but the new format has eight data tracks and one parity track for a total of nine parallel tracks. Data is stored as 8-bit characters, spanning the full width of the tape. Various recording methods have been employed during its lifetime as tape speed and data density increased, including PE, GCR, and NRZI. Tapes come in various sizes up to 3,600 feet (1,100 m) in length.

Magnetic-tape data storage is a system for storing digital information on magnetic tape using digital recording.

<span class="mw-page-title-main">IBM 7080</span>

The IBM 7080 was a variable word length BCD transistor computer in the IBM 700/7000 series commercial architecture line, introduced in August 1961, that provided an upgrade path from the vacuum tube IBM 705 computer.

<span class="mw-page-title-main">IBM 7330</span>

The IBM 7330 Magnetic Tape Unit was IBM's low-cost tape mass storage system through the 1960s. Part of the IBM 7 track family of tape units, it was used mostly on 1400 series computers and the IBM 7040/7044. The 7330 used 12 inch (12.7 mm) magnetic tape up to 2,400 feet (730 m) long wound on reels up to 10+12 inches (266.7 mm) diameter.

<span class="mw-page-title-main">IBM Naval Ordnance Research Calculator</span> 1950s computer

The IBM Naval Ordnance Research Calculator (NORC) was a one-of-a-kind first-generation computer built by IBM for the United States Navy's Bureau of Ordnance. It went into service in December 1954 and was likely the most powerful computer at the time. The Naval Ordnance Research Calculator (NORC), was built at the Watson Scientific Computing Laboratory under the direction of Wallace Eckert.

References

  1. "IBM 727 Magnetic tape unit". IBM.