World Library  
Flag as Inappropriate
Email this Article

Ibm 727

Article Id: WHEBN0006038256
Reproduction Date:

Title: Ibm 727  
Author: World Heritage Encyclopedia
Language: English
Subject: List of IBM products, IBM 7 track, IBM 7080, IBM 702, IBM 700/7000 series
Collection: Ibm 700/7000 Series, Ibm Storage Devices
Publisher: World Heritage Encyclopedia

Ibm 727

An IBM 704 mainframe with IBM 727 tape drives on the left. (image courtesy of LLNL)
Half-inch tape reel with write protect rings

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 The 727 was withdrawn on May 12, 1971.

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.

tracks 6 data, 1 parity
chars/inch 200 characters/inch
Tape speed 75 inches/second
Rewind speed 500 inches/second (average)
Transfer rate 15,000 characters/second
Start time 5 milliseconds
Stop time 5 milliseconds
Width of tape 1/2 inches
Length of reel 2,400 feet
Composition PET film (Mylar) or cellulose acetate base


  • IBM 727 Magnetic tape unit

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.