Editing DECtape (section)

== DECtape II ==
[[Image:DECtape.jpg|thumb|DECtape (top and lower left) and DECtape II (lower right) removable magnetic media]]
'''DECtape II''' was introduced around 1978 and has a similar block structure, but uses a much smaller {{convert|0.150|in|mm|abbr=on}} tape<ref>{{Citation|title=TU58 DECtape II Technical Manual |publisher=Digital Equipment Corporation |year=1979 |url=http://bitsavers.org/pdf/dec/dectape/EK-0TU58-TM-001_TU58tech.pdf |pages=1–5 |url-status=dead |archive-url=https://web.archive.org/web/20100807150030/http://www.bitsavers.org/pdf/dec/dectape/EK-0TU58-TM-001_TU58tech.pdf |archive-date=2010-08-07 }}<!--That's chapter 1 page 5, not pages 1 through 5--></ref> (the same width as an audio [[compact cassette]]). The tape is packaged in a special, pre-formatted [[DC100|DC150]] miniature cartridge consisting of a clear plastic cover mounted on a textured aluminum plate. Cartridge dimensions are {{convert|2+3/8|x|3+3/16|x|1/2|in|mm}}. The TU58 DECtape II drive has an [[RS-232]] [[serial interface]], allowing it to be used with the ordinary serial ports that are very common on Digital's contemporary processors.

Because of its low cost, the TU58 was fitted to several different systems (including the [[VT103]], PDP-11/24 and /44 and the VAX-11/730 and /750) as a DEC-standard device for software product distribution, and for loading [[diagnostic program]]s and [[microcode]]. The first version of the TU58 imposed very severe timing constraints on the unbuffered [[universal asynchronous receiver/transmitter|UART]]s then being used by Digital, but a later firmware revision eased the flow-control problems. The [[RT11]] single-user operating system can be [[booting|bootstrapped]] from a TU58, but the relatively slow access time of the tape drive makes use of the system challenging to an impatient user.

Like its predecessor DECtape, and like the faster RX01 floppies used on the [[VAX-11|VAX-11/780]], a DECtape II cartridge has a capacity of about 256 kilobytes. Unlike the original DECtape media, DECtape II cartridges cannot be formatted on the tape drive transports sold to end-users, and have to be purchased in a factory pre-formatted state.

The TU58 is also used with other computers, such as the [[Automatix]] Autovision [[machine vision]] system and AI32 robot controller. TU58 driver software is available for modern PCs running [[DOS]].<ref>{{Cite web|url=http://www.sparetimegizmos.com/Software/TU58_Driver.htm|title=TU58 Driver|website=www.sparetimegizmos.com}}</ref>

Early production TU58s suffered from some reliability and data interchangeability problems, which were eventually resolved. However, rapid advances in low-cost [[floppy disk]] technology, which had an inherent speed advantage, soon outflanked the DECtape II and rendered it obsolete.