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C00002 00002	Class notes, CS206		4/4/74
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Class notes, CS206		4/4/74

Handout dated 4/6/74 is Handout 6. Pocket reference card. Students
MAY use the two crt terminals upstairs Cassita.

TENEX concepts and trivia:

   JOBS - login creates a job, logout kills the job
   DIRECTORY - identifies user and file storage
   FILE - set of info on disk, identified in directory.
	file NAME consists of <dir>filename.ext;version
	"*" in any field means "anything"
   COMMANDS - various things that the monitor can do for you;
	you can interrupt your program, do TENEX things,
	and then continue the program, provided you haven't
	run another program.

When creating files always use your initials as extension since
	more than one person will be using each directory.
alt≡altomode≡escape≡enter all the same thing. When giving
	command to TENEX, altmode will cause TENEX to complete
	partial command, if possible. If its ok, type carriage return.

	In ILISP, altmode acts as "as many right parentheses as
	needed to balance the entire input" and terminates input.
	ILISP echos altmode as $. 

	At IMSSS, ctrl-D acts as a wait/go-ahead flipflop.

Comments of general interest in file <206LIB>NEWS.TXT latest messages
	are first. tell TENEX 
		TYP⊗ <206LIB>NEWS⊗ (where ⊗ is altmode)
	what will appear on terminal is
		TYPE (FILE) <206LIB>NEWS.TXT;3
	type carriage return, and it'll come out.

DIR, cr - allows subcommands, prompts @@; @@DEL will list all deleted but
	but unEXPUNGED files.

WHERE 19LISP - will tell you about all users logged in under 19LISP.

DELVER cr - this is a PROGRAM which deletes all but latest versions
	of a file.

at end of session, DELETE unwanted files.
Check DIR,cr DEL. If ok, EXPUNGEcr.

ILISP manuals are in.

Read Weisman, CH 1,2,3, 5 (more or less optional)

INTERLISP uses different commands than ILISP; beware!!!


Data structures:
	In numerical programming - usually only numbers and arrays
	In string processing - strings and substrings
	in list processing - using lists

indivisible building block/concept: an ATOM
	any string of letters, numbers and selected characters
	NOT included: ( ) [ ] cr line-feed period
	(N.B. ILISP does not allow atoms to start with digits)

<s-expr> ::= <atom> | (<s-expr> . <s-expr>) | NIL
<list> ::= (<s-expr> . <s-expr>) | NIL

() ≡ NIL is BOTH an atom and a list.

Many representations for lists:
	machine representation
	dot notation
	graph representation ≡ binary tree ≡ little boxes with arrows
	list representation : most commonly used.

Dot notation	List representation 	LISP printout 
(A . (B . NIL))		(A B)		(A B)
(A . B)			none		(A . B)
((A . B) . NIL)		none		((A . B))
NIL			()		NIL
************************************************************
Note to students who wish to use systems other than IMSSS:

If you wish to use some system other than IMSSS you are expected
to be enough of a hacker to cope with the problems that you will
have.  The ILISP system at the A.I.LAB is slightly different from
that at IMSSS (initially we have set up ILISP at IMSSS to use
EVALQUOTE at top level rather than EVAL. ).  Of course monitor
commands are different.

Users who wish to use INTERLISP will have additional problems; there
are incompatibilities between INTERLISP and ILISP that can be at times
obscure. Furthermore, IMSSS TENEX is slightly different in the 
EXEC command language.

All instructional materials, handouts, notes, and homework will
be prepared for IMSSS ILISP. We do not plan on making different
versions for INTERLISP or for other ILISP facilities in general.

Another source of potential problems will be that there will be assignments
which will require files which will exist only at IMSSS. 

THUS: If you are a novice, or are not already familiar with the
system you wish to use, it is NOT RECCOMENDED!!

After all of that disclaimer: Homework turned in from any other
system will be accepted; a REASONABLE FACSIMILE of what ILISP/IMSSS
should be turned in.