BASIC DATACOMPUTER USE V. R. Pratt M.I.T. 5/9/77 BRIEF DESCRIPTION The Datacomputer (DC) is a slow computer in 575 Technology Square, at the CCA (Computer Corporation of America) node of the ARPA network. Its interesting feature is that it has 3 terabits (3,000,000,000,000 bits) of memory. It serves as an archive device for the entire ARPA network. The purpose of this note is to tell you just enough about it so you can use it to store files you don't use regularly but don't want to dump onto magnetic tape. This document presents a simplified model of what is going on in DC, to avoid first-encounter confusion; for more sophisticated use, see the more complete manual residing on .INFO.;DFTP ORDER. Hopefully DC will alleviate the present space crunch on the AI computer. I have been using DC myself for the past five months and have found it an excellent way of uncluttering my directory. TERMINOLOGY, CONVENTIONS, COMMANDS The following section is near the front of this note for handy reference. Skip it on your first reading. Terminology LOCAL The ITS computer you are using REMOTE The Datacomputer (DC) USER Your own node on DC TERSE A minimum of usable information VERBOSE Much information Conventions RUBOUT Within a name: rubs out one character Between names: rubs out whole command ^U Rubs out whole line ^R Retypes line Filenames Must be given in TENEX format whether you are naming local or remote files (thus FOO 27 on your local directory would be typed FOO.27) Remote files appear as FOO.27;2 or more generally as fn1.fn2;vers where fn1 and fn2 (filename 1 and filename 2) are arbitrary strings and vers is the DC-generated version number (which you can generally ignore - it plays the same role essentially as ">" in ITS file names). When it makes sense to talk about sets of files (as opposed to one file), you can name a set by typing * for any or all of fn1, fn2, and vers. Thus you can PUT or GET several files at once. Abbreviations You need only type the first two or three characters of any COMMAND (but not filename) and DC will know what you mean. Thus DE FOO will delete file FOO, CO LABOR will connect you to your LABOR subnode, etc. End-of-word Type a space between words End-of-command Type a carriage-return Commands (For a complete list, see .INFO.;DFTP ORDER) CONNECT connects you to the subnode you want to work on. (e.g. "CONNECT WIDGETS" followed by carriage return). DIRECTORY prints directory of your files on current node (follow it with three spaces). PUT puts a file of yours on DC (e.g. PUT FOO.25 FOO.XYZ) (local first). GET gets a DC file (goes in your ITS directory) (e.g. GET FOO.XYZ FOO.25) (remote first). DELETE deletes a file (e.g. DELETE FOO.XYZ). UNDELETE undoes DELETE (e.g. UNDELETE FOO.XYZ). LIST lists your nodes. "LIST << " (2 spaces at end) will show you your subdirectories. QUIT kill the DFTP job (say "QUIT Y"). LOCAL-CONNECT connects you to an ITS directory other than your own (e.g. LOCAL-CONNECT LIBLSP). USING DC The first thing is to get DC to know about you. Send a message to BEE@MC asking for an account on it. To use DC, just type :DFTP at DDT. This will log you in to DC using your local login name. DC will type [Attaching] and then prompt you with a *. DC is a slow computer, so be patient about this and other operations. Sometimes DC is completely loaded, in which case you will have to wait your turn. Thus after typing :DFTP do ^Z^P and work on something else while waiting. When you get the message "Job DFTP wants the TTY", go back to DFTP. To find out the status of DC (useful when you are not getting attended to with :DFTP and want to know what's up), type :DCSTAT at DDT. You will be given lots of statistics; keep an eye out for a line stating whether DC-203 (the Datacomputer you use) is listening, not listening, or dead. Ignore information about DC-303, which is the old Datacomputer. Before you start storing files on DC you should decide whether or not you want your directory structured. In an unstructured directory, you only have one node, the one representing you, called your USER node (terminology local to this guide), where all your files accumulate. In a structured directory you have various subnodes of your USER node, in each of which you can accumulate files. The advantages of an unstructured directory are that you don't need to remember where you put your files, and you can get a directory listing of all your files with only one command. The advantages of a structured directory are that you have a better idea of what your holdings are on any given topic, you have one more means of talking to DC about a given subset of your holdings (e.g. you can ask for all the files in a given node to be copied from DC to AI, or just those in that node with a given second file name, etc), you run less risk of giving the same name to two files (unlike ITS, this is not catastrophic on DC, which keeps track of same-named-files using version numbers), and you don't have to print out your whole directory just to locate a file whose name you have forgotten but whose classification you remember (a common occurrence). My own directory is structured. If you decide to have a structured directory, you should now connect yourself to whatever subnode you want to work on. Type CONNECT WIDGETS (end all commands with carriage return) to work on your WIDGETS directory. With an unstructured directory, you are already connected to your USER node when you log in, so that no explicit CONNECTion on your part is necessary. To see the directory of the node you are connected to, say DIR followed by three spaces. (DC will type some stuff whose meaning you can dig out of .INFO.;DFTP ORDER if you want to use DIR in fancier ways.) To put FOO > (already on your local directory) on DC, simply say PUT FOO (carriage return) and a copy of FOO > will be put in the node you are are connected to. The copied file will be named FOO.;1 where the item following the "." (nothing in this case) is the remote filename 2 and the item following the ";" is the version number as perceived by DC, which you can ignore. If you want a non-null filename 2 (not essential, but helpful when you want to talk to DC about a class of files in a directory, e.g. if you want later on to get all XYZ files) then say PUT FOO FOO.XYZ and the copied file will be named FOO.XYZ;1. When typing the local and remote filenames in the PUT command, DC will prompt with [As] between the two filenames, so in fact it will appear as though you typed PUT FOO [As] FOO.XYZ If you want to also specify the local filename 2, say it is 27, then type PUT FOO.27 FOO.XYZ or just PUT FOO.27 if you want the remote copy to be called FOO.27 rather than FOO.XYZ. (My preference is to always give a filename 2 which specifies what sort of a file it is, e.g. LSP, PRO (proposal), DOC (documentation), etc.) To get a file from DC, say GET FOO or GET FOO.XYZ (depending on whether the remote copy has a filename 2) and your local directory will end up with a copy of FOO, with a filename 2 of either > if none was specified or XYZ (or whatever) otherwise. As with PUT, you can name both the local and remote files, as in GET FOO.ABC BAZ.XYZ which will get the most recent version of the remote file FOO.BAZ (the one with the highest version number) and name it BAZ XYZ. If you want to get, say, all files with filename 2 LSP, type GET *.LSP where the * indicates that anything will do. Then all LSP files in your remote directory will get copied into your local directory. To delete a file, say DELETE FOO or DELETE FOO.XYZ If you want to revive a deleted file, say UNDELETE FOO which will revive FOO unless your directory has been EXPUNGEd (presumably by you - see .INFO.;DFTP ORDER). To see what nodes you have attached to your USER node, type LIST << followed by two spaces, which will produce something like ITS JONES REPUBLICANS DEMOCRATS LIBERTARIANS indicating that your USER node (JONES) is a subnode of the ITS node (which is itself a subnode of the DC's root node) and you have three subnodes of your own, each containing files. When you are done, type QUIT Y (the Y is in response to the question [Confirm]). This logs you out of DC and closes the network connection. Even this simple task is done slowly by DC, so you may as well do ^Z^P when you've confirmed. The above represents a minimum of what you need to know to use the Datacomputer. For fancier use of DC than this, read .INFO.;DFTP ORDER.