Guide to Extent Types

Extent Type Definitions

Cubic Feet

Megabytes

Gigabytes

Terabytes

Box(es)

Folder(s)

Item(s)

Sheet(s)

Tube(s)

Volume(s)

Cassette(s)

A sealed plastic unit containing a length of audiotape, videotape, film, etc. wound on a pair of spools, for insertion into a recorder or playback device. May be further described in the container summary using the following  terms. For additional options, check the A&AT Record. See also: Guidelines for Processing Collections with Audiovisual Material: Chapter 5, Description in ArchivesSpace

Further information about the type of cassette should be provided in the Container Summary Field.

Container Summary Options (incomplete list)

• Audiocassette
  • 8-track cartridge
  • Digital audio tape
  • Minicassette
  • Microcassette
• Videocassette
  • U-matic
  • VHS
    • Super-VHS
  • Betacam
    • Digital Betacam
    • Betacam-SP
  • Betamax
  • Mini-DV

Flash Drive(s)

Flash Drive(s) — Computer storage devices involving no moving parts in which data is stored in non-volatile memory. Information can be written and retrieved to flash drives more quickly than electromechanical hard drives.

Container Summary Options

 Memory card

 USB flash drives

Hard Drive(s) 

Hard Drive(s) — Devices that house a fixed (non-removable) hard disk for storage and retrieval of digital computer data.

Magnetic Disk(s)

Magnetic Disk(s) — storage device that uses a magnetization process to write, rewrite and access data. For magnetic hard drives use Hard Drive(s)

Container Summary Options

• Floppy disk (Specify in dimensions: 3.5”, 5.25”, 8”, or other non-standard)
• Zip disk
• Jaz disk

Optical Disc(s)

— electronic data storage medium that can be written to and read from using a low-powered laser beam

Container summary:

 DVD

 CD

 Bluray

 Laserdisc

 MiniDisc

Reel(s)

— a cylinder on which film, wire, thread, or other flexible materials can be wound.

 Container summary:

Microfilm

 Sound recordings

• Example: Dimensions: Tape width: ¼”, Reel diameter: 3”, Duration: maximum length of storage media (for instance 90 minutes)

 Film 

• Example: Dimensions: 18mm, Reel diameter: 10.5”

Guides for identifying media

• AV and some digital media: https://psap.library.illinois.edu/collection-id-guide/

• Digital media: https://lib.utsa.edu/knowyourmedia/ 

https://obsoletemedia.org/