Using a CP/M Simulator

Since I started the project I started searching for CP/M simulators. In order to boot and use my system I needed a tool to build CP/M (assembling the CCP,BDOS,CBIOS and CBOOT), and transfering files to the disks. I found many that are a bit outdated here, and two great simulators with loads of cp/m software ready to run: Z80pack and SIMH/Altairz80 .

I setteld with Altair Z80 SIMH because it suited better my project. On the processor side allows you to change form the standard Z80 of most simulators to a 8080 processor, you can easily reduce the memory to 32Kb, it also has the boot disks and source (although in Z80 format) for CP/M 2.2, CP/M 3, and MP/M II. Finally and also very important, not only it supports the disk format I wanted to use (3.5 inch 1.44Mb, i.e. as used by P112) as also supports accessing the floppy disk directly.

As recommended here, I used a image file to transfer the files and then used NTRAWRITE to transfer the files to the floppy. I am using a USB 3.5 inch drive and the other usual tools to read and write CP/M disks didn't work as they used direct access to the UPD765 in regular PC.
The procedure is easy, start altairz80 and type in:
sim> set hdsk1 format=p112
sim> attach hdsk1 \\.\B:
sim> show hdsk1
HDSK1, 1474KB, attached to \\.\B:, P112, WRTENB, QUIET,
sim> go

At the moment I can only use CP/M 3 for reading and writing the disk images, because for CP/M 2.2 one needs to adapt the bios specifically for each hard disk.
When all the files have been transferred to the disk image, close the simulator and use NTrawrite to write the floppy image into the floppy.


More on Electric Bikes

The electric bicycle dream is not over yet although "in times like these" one must rethink when to invest or buy something. The three essential questions in times of crisis must be answered:
- do I need it?
- will i use it reasonably? (in cases you're in debt already, the question is "can I afford it?")
- can I get a better price?

Well a better price in the drive unit is certainly needed here are the other sites I've found:

Have a great week.