About
A development disc from Crystal Research, the company that wrote the Einstein’s DOS and BASIC, in use on their bench from the spring of 1984 into 1986. It boots XtalDOS 2.02 and carries Xtal BASIC 5.00, a version we have not found on any other disc, and underneath its live files, deleted but intact, are the Einstein master disc programs as they stood in April 1984, three months before the machine went on sale: Hangman V007 by David Wess, Snakes V008 by Nigel Deakin, Mark Bailey’s clock, and Demo, Othello and the Einstein introduction, all at version 0.2. The story of the disc and its rebuild is told in The Master Disc Before It Was Finished.
What Is in the Download
Four disc images and the notes to go with them:
EINMAST5-original.dsk, the image as published: 34 of 40 tracks, with tracks 3 to 7 and 11 absent and nine bad sectors elsewhere.EINMAST5-rebuilt.dsk, a faithful 40 track image with the 60 unread sectors filled and flagged bad, nothing undeleted and nothing repaired.EINMAST5-recovery.dsk, the same with the eleven deleted entries whose data was all present restored to the directory, and Disco Dan’s four bad sectors repaired from the library’s copy of the same program. This is the one to boot.EINMAST5-working.dsk, as recovery with the bad flag cleared on Xtal BASIC 5.00’s one damaged sector so the DOS will load it; about 360 bytes of that sector are unverified.
Plus a README with the full account, the checksums, and the GNU licence text from the source site.
What Is on the Disc
Live: DISCODAN.COM (its title screen credits Gem Software, “Coding & Design by D. White & J. Line”), CHUCKY.COM (Chuckie Egg), TERMINAL V0.1, RTTY.XBS (a radio teletype reader), DEBUG.COM (Cromemco), LOAD.COM (Digital Research), HEXIN and HEXOUT, DEFINE.XBS (a shape table editor), SQUARE and FLOWER, COPY and BACKUP. Restored from deleted: the six April 1984 master programs, XBAS.COM (Xtal BASIC 5.00), three physics exercises called MARK1 to MARK111, and TEST. Lost on the missing tracks: OH.COM, the April 1984 PICPEN.XBS and most of the April 1984 EINSTEIN.XBS.
Running It
Boot the recovery image. It signs on “XtalDOS 2.02 (C) Xtal 1983-86”; DIR lists 31 entries; DISCODAN and HEXIN run. XBAS stops with Bad Data at its flagged sector on the recovery image, as it should; use the working image for a BASIC that signs on. To run the 1984 programs under a BASIC of their own age, boot a TC01 System Master in drive 0 with this disc in drive 1, type XBAS, then RUN "1:HANGMAN", RUN "1:SNAKES", RUN "1:CLOCK" or RUN "1:OTHELLO". All tested in MAME 0.289, none on real hardware.
Source and Credits
The original image is one of the set Trevor Brownen, founder of Crystal Research, published on his site xtal.info under the GNU General Public Licence, with the note that the copies have sector faults and that it may be possible to put complete discs together from them. Rebuilt by TatungBytes in October 2026. XtalDOS and Xtal BASIC remain Crystal Research’s copyright, the master disc programs Tatung’s and their named authors’, and the other programs their publishers’; the file will be taken down on request from any rights holder.
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