This is a simulator for my Altair 8800, which allows you to mount and
"boot" diskette images and to use them from your PC screen exactly as
you would on my actual Altair machine.

Note: This is not a "pretty" graphical simulator for the Altair, although
it does a not-bad job of rendering the front panel activity in text mode.
It is mainly intended to provide an experience of my Altair from the point
of view that you are sitting in front of my ADM-3A terminal - for this
reason the simulation runs in a TEXT mode screen. The large fixed pitch
characters of text mode provide a fairly accurate reproduction of the "feel"
of using the terminals that were available at that time.

I have not yet written extensive documentation for the simulator, however
there is fairly decent online help available from within it.

Being a text mode program, the simulator and tools are best used from a
command line prompt (If you are not comfortable with a command line prompt
and text mode screens, you will probably not find this material very useful,
and you definately not have liked the Altair - or any other computer from
this time period).

NOTE: For a "pretty picture" Altair simulator, please have a look at Richard
Cini's Altair32 which is presented on this cd in the \OTHRSTUF direcory.

Files in this directory:
------------------------
ALTAIR.COM   - Altair 8800 simulator
ALTAIR.HLP   - Help file for ""
NSI.COM      - Northstar disk Image - file transfer utility
DISKIMGS.TXT - Summary of diskette images
*.NSI        - Diskette image files


Booting the Virtual Altair
--------------------------
I have provided three primary BOOT disks, although several of the other
disks will also boot:

   DMF    - My DMF Operating System
   NSTAR  - NorthStar DOS
   FORTH  - A forth system

To boot a disk, just mount it on drive 1 (either by F7 command within
ALTAIR, or by R/W=command line parameter. Then execute the boot rom code
at address E900.

To do this via the Front panel, set E900 on the data/address switches,
then activate "exaMine" (M) to load E900 into the program counter, and
then "Go" (G) to start the CPU executing.

If you are NOT using a serial port connection for the console terminal
you may want to immediately use F2 to activate to switch to the full
screen view of the built in ADM-3A in order to view the OS boot messages.

Note that the virtual Altair sets the default switch settings to E900,
so that you just have to hit exaMine & Go to boot the system if you have
not changed them (My original Altair has switches set to E900 almost
all the time.)

SOFTWARE NOTES
--------------
Most of the software is pretty self explainatory, and I have provided
scans all of the documentation that I have (which is pretty complete)
on my "old computer museum" web site (See link at www.dunfield.com).
Here are a few notes about things which may not be entirely obvious.

- The NSMASTR disk is the original NorthStar DOS unpersonalized distribution
  disk - this means that it has no I/O functions for the system console. It
  boots, but immediately hangs in an infinite loop where the console output
  function should be. The idea is that you can boot this disk, then halt the
  system and use the front panel to patch in the I/O functions, then start
  up the DOS and use it to save itself back to another disk. This procedure
  is described in the NorthSTar system software manual.
  NOTE: This is a good excercise to see how you "got going" with a personal
        computer in the late 70's - for a realistic experience, try doing it
        using only the front panel switch controls.

- The "as shipped" NorthStar BASIC assumes only 16k of system memory.
  Many of the games require more than this. I have already set the upper
  memory limit on copy of BASIC on my NSTAR primary boot disk to DFFF,
  however if you use other copies of BASIC, you may experience "TOO LARGE"
  errors, and have to use the MEMSET command.

- If you try the XEK editor, note that it simply "screws up", printing
  trash etc. if you do not first use the "F" command to create a memory
  file. (XEK takes a bit of getting used to).

- Many of the BASIC games require access to the disk, and expect the disk
  to be mounted in drive 1. Normally, you boot, run BASIC and then remove
  the boot disk from drive 1 and insert the games disk.

- You can mount drives "on the fly" in the simulator by pressing F3 to stop
  the simulation, then F7 to access the disk mount function. After selecting
  a drive and diskette image, press 'G' and the simulation will continue.


Dunfield Development Services (DDS) offers software and firmware
development services specializing in systems and embedded applications.
For more information, visit: http://www.dunfield.com
