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TCP for MacWorks

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D.Finni:
I think that we've got enough options for the serial interface, and it won't be the biggest challenge.

I think that the biggest challenge is the effort and knowledge required to write a new graphical Lisa tool. And following that, which application should we do first? Telnet seems like the best choice to me.

stepleton:
Telnet would not be hard from a UI perspective, relatively speaking. The QuickPort library provides text-in-a-window capability with very little effort beyond basic Pascal console I/O. You even get terminal emulation for free --- I think VT100 and Soroc.

rayarachelian:
So after telnet, how hard would it be to do something like an ftp client? Doesn't have to be as good as ncftp but as long as it does binary and mget/mput, that would be fantastic, for example, you could use it to back up a whole ProFile.

D.Finni:

--- Quote from: stepleton on February 18, 2021, 04:34:01 pm ---The QuickPort library provides text-in-a-window capability with very little effort beyond basic Pascal console I/O.

--- End quote ---
That sounds like a great place to start.


--- Quote from: rayarachelian on February 18, 2021, 05:51:47 pm ---So after telnet, how hard would it be to do something like an ftp client? Doesn't have to be as good as ncftp but as long as it does binary and mget/mput, that would be fantastic, for example, you could use it to back up a whole ProFile.

--- End quote ---
Now FTP is where it starts to get tricky, and this is a protocol which pre-dates TCP/IP and as a result has a lot of baggage. If your goal is to back up a ProFile, I think you'd be better off inventing your own protocol. Or just start reading and sending each 512-byte data block in sequence as soon as a client connects to the Lisa's listening TCP port.

Then to get fancy, you add an option to type in a filename on the Lisa, and then the program sends just that file on the TCP socket instead of the whole drive.

stepleton:
There's a (predictable) additional issue that the Lisa FS has metadata that you won't find on other operating systems. Besides the usual stuff you see in a file listing (creation time, modification time, and so on), there's also "type" and "subtype" fields (reminds me of filetype and creator for Macintosh) (see PDF pages 36-38, 155, 184-186 of the Workshop 3.0 system software manual), and you can also have a "label" of up to 127 bytes (PDF page 46).

I don't know what anyone used these fields for, but when I made a (somewhat buggy) file downloading utility (which used YMODEM over a null modem cable instead of TCP/IP), my solution was to package everything on the fly into a tar archive with three "files" inside. One file was a text file holding the filesystem metadata, one file was the contents of the label, and the final file was the actual file contents.

The Lisa's format for text files is a little weird --- it's faintly block oriented (files are always sized in multiples of 1K, IIRC), and it uses run-length encoding for runs of spaces. I'm still trying to track down where I saw the format documented (the documentation calls it the "One World Text File Format" or something like that), but here's a bit of Python that can decode it.

Lastly, there is the issue of protected files, which the Lisa OS will refuse to let you open. These files are interesting ones like Pascal compiler (Pascal.obj) and the various tools. It's possible that this more recently-discovered mechanism for jumping into supervisor mode can offer a workaround.


(Since we were talking about it earlier: the system software manual has the programmer's documentation for the QuickPort library, PDF pages 336-392.)

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