OS ROM XE

[edelro]

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Hallo,
kann jemand sagen was an dem OS C300717 (XE Rev 3) anders ist als bei OS CO61598B ?
(Und für die Witzbolde: Ich meine nicht die Bezeichnung )
Danke

[DjayBee]

Hol dir das OS-Archiv von Kr0tki. Darin befindet sich auch eine README.html, die höchstwahrscheinlich die Antwort enthält.

https://forums.atariage.com/topic/20113 ... nt-5730231

[HiassofT]

Detaillierte Infos zu den Atari ROM Versionen findest Du im README.html von kr0tki's OS Source Code Paket. Die letzte Version gibt's hier:
https://forums.atariage.com/topic/20113 ... nt-5730231

Zum Rev.3 OS steht da folgende Beschreibung:

1985-03-01: XE OS Rev. 3 ready

ROM identifier: Date 1985-03-01, CPU series 2, Part BB000001, Rev. 3

Atari has developed a new revision of the OS, with the date in the ROM identifier being 1 March 1985. It was based on Revision 2 from the 800XL, and did not contain any of the changes and additions introduced later. Apparently the new management of Atari had decided to abandon any significant development of the OS.

Compared to Revision 2, this OS version contains changes in the Self Test to support testing of expanded memory in the 130XE computer, which was available by setting bits 2-3 of PORTB. The Memory Test does no longer flash the (now non-existing) console LEDs during the test - instead it tests the additional memory banks after finishing with the main RAM, and displays the results in the form of four green or red horizontal bars below the main RAM display, one for each bank. But the testing was programmed incorrectly - the values in the TXEB table are so defined that the test uses bits 1-2 of PORTB instead of 3-4. While this is invisible for the user, the test effectively checks only 2 of the 4 banks, and switches BASIC on and off in the meantime.

Other than that, the Memory Test had its delay loops shortened so that it performs faster.

The Keyboard Test was also updated, to match the keyboard layout to the XE keyboard, although this was done independently to the previous attempt in XL OS Revision 5. Also, the easter egg in All Tests was updated so that the keyboard now types out "Copyright1985Atari".

Overall, parts of Self Test were rewritten to free ROM space for new features. The Audio-Visual Test was subject to the most refactoring, and the STH (Self-test Hardware) routine was removed because it only jumped to EST (Execute Self-test).

Apart from the Self Test, XE Revision 3 incorporates one bugfix originally developed in XL Rev. 3, namely the fix in the SEN (Send) routine in checksum computation - the only change retained from all the development in 1984. Otherwise this revision is identical to XL Revision 2.

The XE Rev. 3 OS would be produced in the form of a single ROM chip:

C300717 - 16 KB

It would be included only in later 65XE and 130XE computers, and in all 800XE units. Apparently it reached the market quite late, possibly even after the XEGS shipped (which had rev. 4 built in), when Atari Corp. started moving its focus, and production volume, to the European (especially Eastern) market instead of the dwindling U.S. one. As a result this OS revision is more common in PAL systems than in NTSC ones.

so long,

Hias

[edelro]

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Vielen Dank

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