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235:-inch covered/notch not present = protected). A common practice with single-sided floppies was to punch a second notch on the opposite side of the disk to enable use of both sides of the media, creating a
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reels, introduced in the 1950s, had a circular groove on one side of the reel, into which a soft plastic ring had to be placed in order to write on the tape. ("No ring, no write.")
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sometimes have a small switch, though this has become uncommon. An example of a USB flash drive that supported write protection via a switch is the
Transcend JetFlash series.
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Write-protection is typically enforced by the hardware. In the case of computer devices, attempting to violate it will return an error to the
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221:-inch floppies can have, respectively, write-protect and write-enable notches on the right side (8-inch punched = protected;
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From top to bottom: an unprotected Type I cassette, an unprotected Type II, an unprotected Type IV, and a protected Type IV.
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EZ-drive (135 & 250 MB) disks were write-protected using a small metal switch on the rear of the disk at the bottom.
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in order to maintain the integrity of data storage devices. By preventing all write operations to the device, e.g. a
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Hardware write blocking was invented by Mark Menz and Steve Bress (US patent 6,813,682 and EU patent EP1,342,145).
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as appropriate, or sometimes by physically altering the media transport to ignore the write-protect mechanism.
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on a device. Most commercial software, audio and video on writeable media is write-protected when distributed.
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while some tape recorders physically lock the record button when a write-protected cassette is present.
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tape cartridges had a small sliding tab on the top left hand corner on the front face of the cartridge.
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methods are used; however, software blocking is generally not as reliable, due to human error.
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Extensively, media that, by means of design, can't operate outside from this mode:
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These mechanisms are intended to prevent only accidental data loss or attacks by
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have tabs on the top/rear edge that can be broken off (uncovered = protected).
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is any physical mechanism that prevents writing, modifying, or erasing
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IBM tape reel with white write ring in place, and an extra yellow ring.
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Write blocking, a subset of write protection, is a technique used in
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have a sliding tab in a window on the right side (open = protected).
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Write protection for computer long-term memory devices
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were write-protected using the IomegaWare software.
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147:Learn how and when to remove this message
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16:Protection for the overwriting of data
295:have a sliding tab on the rear edge.
85:adding citations to reliable sources
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53:" floppy disk write protect tabs.
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72:needs additional citations for
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343:or by creating one with a
392:(US patent 6,813,682).
378:software write-blocking
430:Computer storage media
410:Copyright infringement
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96:"Write protection"
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257:floppy disks
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79:Please help
74:verification
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237:flippy disk
39:A sheet of
384:References
368:hard drive
107:newspapers
266:Zip disks
137:July 2010
424:Category
404:See also
394:Archived
170:Examples
272:Syquest
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121:scholar
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331:, etc.
299:Iomega
288:, and
282:Video8
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255:-inch
207:8 and
187:-inch
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325:DVD-R
302:ditto
278:VHS-C
128:JSTOR
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197:and
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100:news
286:Hi8
199:VHS
176:IBM
83:by
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