Date   : Sun, 08 May 1983 20:27:00 EDT
From   : Keith Petersen <W8SDZ@mit-mc.arpa>
Subject: More re FTP and .COM files on ITS

More from GZ@MC about ITS .COM file format:

From: Gail Zacharias <GZ at mit-mc.arpa>
Re:   ITS binary format

There are two separate issues here.  First is packing 8 bit bytes into
PDP-10's 36 bit words.  This is unavoidable, standard, and the ITS ftp
server deals with it just fine.  The problem is getting the unix user
end to tell ITS to do it. SEE BELOW FOR HOW TO DO THIS.

The second problem is the 4-byte header put in the binary CP/M files
stored in the CPM; directory. This has nothing to do with ITS, and was
a decision made by those involved with maintaining this directory and
related programs.  SEE BELOW FOR HOW TO DEAL WITH THIS.

I might suggest that someone fix umodem to recognize those header
bytes (they are 93H,3AH,D8H,00H) and strip them off.  umodem could
also use them for their intended purpose, differentiating between
ascii and binary files, so the user wouldn't have to give a "b" switch
(I assume that's what the -sb below does). The TOPS-20 modem program
already does this.

Anyhow, unix people, here are the answers:

From: bridger at rand-unix
To:   Gail Zacharias <GZ>
Re:   downloading .com files

Thanks for the protocol, which enabled our resident expert, jim
guyton, to develop this method of downloading binary files. At
Rand-unix we are using a version of the BBN ftp program.

1. to retrieve "AR14:CPM;NAMEXX COM" from mit-mc:

       ftp mit-mc
       type i
       quote type "l 8"
       get "AR14:CPM;NAMEXX COM" longnamexx.com
       bye

2. to strip off the 4 header bytes:

       dd
       if=longnamexx.com
       of=namexx.com
       bs=1
       skip=4

3. to download to a cpm machine:

       umodem -sb namexx.com

                                       bridger

--end--