Since you will be using Putty to access the Altair, attach the USB cable to the Altair and then to your computer. Find which device is being used for the USB port in question. For me it's something like: /dev/ttyACM0. Check that the Connection type is Serial and the Speed should be 115200.
Launch putty with the aforementioned parameters. Lights should flash on the Altair. All switches should be 0. Push AUX1 down and you should be in.
(NB. AUX1 is left, AUX2 - right)
You can enter any of the programs on display by selecting the appropriate switches and pushing AUX1 down.
(NB. To stop all activity or a program: Stop + Reset)
Stop whatever the Altair is doing – raise “Stop”, then raise “Reset”.
Mount emulated disk 1 in drive 0 – switch 12 up, switch 0 up (all other switches down).
AUX2 down to load disk.
Terminal will say “[mounted disk ‘DISK01.DSK: CP/M (63k)’ in drive 0]”
To run bootable disk – switch 3 up (all others down).
AUX1 down. This will install the Disk Boot ROM and boot disk 0.
Terminal will load CP/M and show command prompt “A>”
This is *genuine* CP/M, so you can find lots of resources on the internet that will show you what to do.
A few things to try:
Type “DIR” to get a directory from the disk.
Type “DEMO”. Yes, kind of pointless.
Type “LADDER”. Basically an ASCII version of Donkey Kong.
Type “MBASIC” to load BASIC-80. “FILES” gives you a directory. RUN “STARTRK.BAS” loads and runs Star Trek. “SYSTEM” exits to CP/M prompt.
Combo Disk Boot Loader / MITS Disk Controller (1000)
(when entering this press enter for Memory Size, capital O for LinePrinter, and enter for the rest.