[6] While it works adequately for storing user files, it does not preserve the baud rate of the recording, precise timing information or the non-standard data streams used in copy protected titles.
In a 2010 post to the Stardot forum, Harte explained at length his reasons for creating the format: being the first to address emulation of the Acorn Electron and its primary medium, tape, Harte wanted a fine-grained and technically optimal representation of media, compared to existing ad hoc formats; and to package the multiple media elements of a software release into a single file, so that downloading a UEF is "more like obtaining the original product".
A UEF file consists of a fixed length header that identifies itself, followed by a linked list of chunks containing the data of interest.
The latter two may change within a published recording, and their absolute values depend on the tape player, amplifier and sound card used to digitise the signal.
This feature is really only for emulation use of UEF files and ignoring bit multiplexing will have no effect on the accuracy of your tool to original hardware.One salient application mentioned by Harte is to superimpose "new graphics on old games",[9] and a single example, a 256-colour enhanced Daredevil Dennis, is available from StairwayToHell.com to run in ElectrEm.
Inlay scan chunks, intended as a file preview, hold a raw bitmap of the cover art although anything beyond a thumbnail can take up more data than a typical game.
The UEF author can also provide the text of an instruction booklet or a URL for more information, a short title for display, minimum machine specification and keyboard mapping for the enclosed software; and where a game does not use the whole screen, the coordinates of the visible area can be given.
MakeUEF is a Windows application written by Thomas Harte and expanded by Fraser Ross to convert audio samples into UEF files.
An 'amateur' version reads WAV files or a live signal played to the sound card, and transcribes only standard data blocks with accuracy.
[8] The 'professional' grade accepts only CSW files, which represent waves preprocessed into rectangular pulse trains, but it encodes all audio information supported by the UEF specification.
[8] Although the file format was more capable, supporting "gap lengths" since February 2001 at the latest,[10] only "program data" was retained by MakeUEF prior to version 1.0.
The GoMMC[13] and GoSDC hardware extensions, produced by John Kortink from 2004, provide a virtual cassette playing capability.
[14] In February 2012, Martin Barr released version 5.0 of UPURS, a ROM based suite of utilities to aid data transfer to real BBC Microcomputers.