Tatung 256 System Disc (XtalDOS 2.05E)

Xtal System 5 for the Tatung Einstein 256: XtalDOS 2.05E and Xtal BASIC 5.02E, Crystal Research's versions of its DOS and BASIC for the 256, with the System 5 tool set. Einstein Monthly reported them in Vol 1 No 3 (about September 1987, page 2), in Vic Day's “Golden Disc” award to A J Cornish of Crystal Research: “a modified DOS, DOS 2.05e especially for the 256 which included all the patches for 80 column working”, with “a 176k Ram disc” on drive 2 that “works in modes 0 to 2”. The magazine called it experimental. Paul Botley pointed us back to it, and we have now tested it in MAME.

What We Found

• A 176K RAM disc on drive 2. DIR 2: answers “0k Size, 174k Free, 176k Total”. It lives in the 256's video memory, in eleven 16K banks, leaving the first 16K to the screen, and the DOS clears it when it starts from the disc, so nothing on it survives a reset.
• Screen modes. Both Xtal BASIC 5.02E and the 256's EBASIC V4.50 save to it and load from it. In EBASIC it survives SCREEN 2; after SCREEN 3 or SCREEN 5 a load from it finds nothing, and going to SCREEN 5 and back erases it.
• 80 columns. BASIC 5.02E differs from 5.02 in one patch: its test for Tatung's 80 column card always passes, so PRINT CHR$(16) switches a 256 to 80 column text, where 5.02 ignores it. The compiler's run time XR.COM carries the same patch and signs on as 5.10E.
• 256 only. The DOS reads the MOS ROM before it starts and stops with BOOT ERROR on a TC-01 with MOS 1.2.
• The other fourteen files are byte for byte those on X-Master.

Running It

Boot it on an Einstein 256, or in MAME with the einst256 driver and the MOS 2.1 ROM. It signs on “XtalDOS 2.05E (C) Xtal 1983-87”; type XBAS for BASIC and DIR 2: for the RAM disc. Not tested on real hardware.

About This Image

Three images, 256MAST, 256MAST2 and 256MAST3, are one identical file, and every one of its 400 sectors reads clean; the copy here was checked against all three. A fourth, 256SYT5, is the same release: it differs only in the three byte serial stamp Crystal put in its DOS and in each of its programs.

Source and Credits

From the disc images Trevor Brownen, founder of Crystal Research, published on his site xtal.info under the GNU General Public Licence, and from Mike's Archive, with thanks to both. XtalDOS and Xtal BASIC remain the copyright of Crystal Research; the file will be taken down on request from any rights holder.