Multiple Choice Practice Questions
1. To represent a number between 0 and 65535 in binary you need
(a) Two bytes of memory, with unsigned binary notation.
(b) Two bytes of memory with signed binary notation.
(c) One byte of memory, with unsigned binary notation.
(d) One byte of memory, with signed binary notation.
2. The four binary digits 1011 can be represented by the single hexadecimal digit
(a) 8.
(b) 9.
(c) A.
(d) B.
3. The number 123 will require the largest amount of memory if it is stored as
(a) Hexadecimal.
(b) Binary coded decimal.
(c) ASCII.
(d) Binary.
4. A positive number, when stored in signed binary, will always
(a) Start with a binary 1.
(b) Start with a binary 0.
(c) End with a binary 1.
(d) End with a binary 0.
5. You can use the CMS network if you have a valid userid, and if you enter the correct password. This
implies that the system will not allow you to log on exactly when
(a) You don't have a valid userid.
(b) You enter the wrong password.
(c) You have no valid userid or enter the wrong password.
(d) You have no valid userid and enter the wrong password.
7. If a 32-bit address bus connects the CPU with RAM, this implies that
(a) At most 4 gigabytes of memory can be accessed.
(b) At most 64 kilobytes of memory can be accessed.
(c) 2 bytes of data can be retrieved at once from an address.
(d) 4 bytes of data can be retrieved at once from an address.
HND 1 CSA EXAMINATION 1996
EXAMINERS: PMS & CG
PAGE
1
Questions 8 to 11.
Assembler Mnemonics
SET x
STA n
ADD n
SUB n
CMP x
Set the accumulator to the absolute value x
Store the accumulator in memory location n
Add the contents of memory location n to the accumulator
Subtract ... etc
Compare A with the value x and set the flags register as follows
F = 1 if A-x is positive ( i.e. 1,2 ... )
F = 0 if A-x is zero
F = -1 if A-x is negative
INC n Increment the contents of memory location n
DEC n Decrement the contents of memory location n
JMP l Go and execute the instruction labelled l
JP l
Go and execute the instruction labelled l if F = 1
JE l
Go and execute the instruction labelled l if F = 0
JN l Go and execute the instruction labelled l if F = -1
STOP Stop the machine's execution cycle
Initially location X holds the value 12, location Y holds the value 4, location D holds the value 0 and the
accumulator holds the value of 17. Then the following assembly instructions are executed (see appendix for
the meaning of each code).
LDA
SUB
STA
INC
X
Y
X
D
What will the final values be in;
8. The accumulator?
A)
B)
C)
D)
4
0
12
8
9. X?
A)
B)
C)
D)
1
8
4
12
HND 1 CSA EXAMINATION 1996
EXAMINERS: PMS & CG
PAGE
2
10. Y?
A)
B)
C)
D)
8
1
4
0
11. D?
A)
B)
C)
D)
12.
0
1
8
12
To represent a number between 0 and 255 in binary you need
(a) Two bytes of memory, with unsigned binary notation.
(b) Two bytes of memory with signed binary notation.
(c) One byte of memory, with unsigned binary notation.
(d) One byte of memory, with signed binary notation.
13.
The decimal number 13 can be represented by the single hexadecimal digit
(a) A.
(b) B.
(c) C.
(d) D.
14.
The number 170 will require the smallest amount of memory if it is stored as
(a) RAM.
(b) Binary coded decimal.
(c) Signed binary.
(d) Unsigned binary.
15.
A negative number, when stored in signed binary, will always
(a) End with a binary 1.
(b) End with a binary 0.
(c) Start with a binary 1.
(d) Start with a binary 0.
16.
You cannot write a file to a floppy disk if the write-protect tab is on, or if there is some problem with
the drive. This is the same as saying you can write to the disk if
(a) The write protect tab is on and there is a problem with the drive.
(b) The write protect tab is on or there is a problem with the drive.
(c) The write protect tab is off and there is no problem with the drive.
(d) The write protect tab is off or there is no problem with the drive.
HND 1 CSA EXAMINATION 1996
EXAMINERS: PMS & CG
PAGE
3
17.
The best description of the memory data register is the register where
(a) Addresses of instructions and data are held.
(b) Addresses of data are held.
(c) Instructions and data are held.
(d) Data are held.
18. To represent a number between -32000 and 32000 in binary you need
(a) Two bytes of memory, with unsigned binary notation.
(b) Two bytes of memory, with signed binary notation.
(c) One byte of memory, with unsigned binary notation.
(d) One byte of memory, with signed binary notation.
19. The four binary digits 1010 can be represented by the single hexadecimal digit
(a) 8.
(b) 9.
(c) A.
(d) B.
20. The number 123 will require the smallest amount of memory if it is stored as
(a) JPEG.
(b) Binary coded decimal.
(c) ASCII.
(d) Binary.
21. If a 32-bit data bus connects the CPU with RAM, this implies that
(a) At most 4 gigabytes of memory can be accessed.
(b) At most 64 kilobytes of memory can be accessed.
(c) 2 bytes of data can be retrieved at once from an address.
(d) 4 bytes of data can be retrieved at once from an address.
HND 1 CSA EXAMINATION 1996
EXAMINERS: PMS & CG
PAGE
4