CS1011 & CS1041 - August/September 1998 - Pete Jinks

Students taking CS1011 answer Question 1 and one other question from Section A.
Students taking CS1041 answer Question 4 from Section B.
Answer each section in a separate answer book.

	Section A: Answer this section in a separate answer book.

1.	Fill in the blanks in the following sentences. Indicate your answers
	by writing down the part letters (a) to (t) and (A) to (T) in order
	and for each, a suitable missing word, number or phrase. Each part
	is worth half a mark.					[20 marks

		This is only the first half of question 1.
		Peter Capon writes the second half.

	MU0 is a simple computer, consisting of two main components, the
	(a)_____ and memory. MU0 instructions can be classified into those
	that mainly use the (b)_____ register, such as (c)_____, and those
	that mainly use the (d)_____ register, such as (e)_____.

	In operating systems, such as UNIX, (f)_____ are used to store
	information, and are collected together in directories. Because
	(g)_____, the filestore is referred to as being tree-structured.

	In the (h)_____ century, Babbage reinvented the concept of the
	Difference Engine, used to (i)_____, and invented the concept of the
	(j)_____.

	The programming languages (k)_____, (l)_____ and (m)_____ are
	examples of the imperative, functional and logic paradigms
	respectively. Of these three paradigms, (n)_____ is/are also
	described as procedural, and (o)_____ is/are also described as
	declarative.

	Programs written in a high level language are translated to (p)_____
	by a compiler. This usually contains three analysis phases: lexical,
	where (q)_____, syntactic, where (r)_____, and semantic, where
	(s)_____. These three phases are then usually followed by the
	(t)_____ phase.


2.	Answer THREE of the following parts in as much detail as you can
	in the time available. Each part is worth the same amount.    [20 marks

 a.	Detail the steps required to locate, access, decode and execute a
	ADD instruction in the MU0 computer. How would the steps required
	differ for a JMP instruction?

	State clearly the movement of information between the components of
	the MU0 computer at each step. Why are most such movements of
	information routed via the ALU, instead of using separate
	special-purpose routes?

 b.	Write a sequence of MU0 assembly language instructions that will
	divide one positive integer (x) by another (y) to give an approximate
	result. Base your answer on the following algorithm:

		/* divide x by y to give result */
		result= 0
		if (y==0) stop
		repeat
		    x= x-y
		    if (x<0) stop
		    result= result+1

	Remember to declare any variables that you use (including x and y).
	Ignore any problems that might arise from values being too big to
	fit in a word. Assume that your program will be modified by the user
	to put specific values into the variables x and y. Marks are awarded
	for the correctness of your MU0 instructions, not their efficiency.

 c.	Programmers using imperative languages have to write programs in a
	different way from programmers using functional languages, even
	though the languages share some features. Describe some of the
	features that most imperative languages and functional languages
	share. Describe some of the differences between programs written in
	an imperative language and in a functional language.

 d.	Explain how a product-number is encoded as an EAN bar-code, and how
	the bar-code is decoded. Describe how the information obtained is
	processed in a typical EPOS system in a shop.

Question 3 is written by Peter Capon.

	Section B: Answer this section in a separate answer book.

Question 4, for CS1041, is written by John Latham.