[Simh] Way out idea for simh

[Sampsa Laine]

> If you want shares access the host filesystem, look to 'nfs'. If the emulated system doesn't already have shared filesystem already, you are probably going to be fighting such things as the disk caching code. File system corruption is very likely to occur.
> 

A device like that on the Altair that allows you to read and write host OS files isn’t that impossible to implement, we can probably reuse some of the existing code.

Basically the guest OS has a READ, DIR, and WRITE/APPEND utility written for it to use that device.

> A lot of the simulated OS's have more basic problems that just making the raw data available to the host OS. VMS doesn't store anything, including text files, in a "stream of byte" form. Others have 6 or 9-bit bytes. Then there is ASCII (multiple variants) EBCDIC (multiple variants), BAUDOUT, etc.

They had this problem when they implemented “netatalk” (AppleTalk for UNIX) so what you COULD do is store the file’s metadata in a related file, so FOOBAR.DAT has a ._FOOBAR.DAT metadata file that describes its structure.

> 
> I think it would be more advantageous to write disk image manipulation routines to insert/extract files to the simulated disk images (while simulator is not running).
> 

Those would be useful and already exist for Files-11 for example.

My proposal is this:

- The simulator has a device (maybe similar to a serial port as mentioned before) to which commands can be issued
- The device is attached to a directory on the host OS
- There are utilities (READ/COPY, WRITE/APPEND, DELETE, DIR etc) on the guest OS that talk to the device (maybe in one utility, maybe several commands - Altair CP/M has a R and W utility). They communicate the structure of the file which is stored on the host OS in a second file. There could also be an “EXPORT” command that simply writes out a stream of bytes that is easily readable by the host OS.

Just my $0.02..

Sampsa
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