Quiz 18.2

DIRECTIONS: Read each question carefully. Then click on the dot next to the answer that most closely fits the question. Try to answer all questions on this quiz and when you are done, click on the grade me button at the bottom.

Coverage: Section 18.2

  1. Which of the following is not a group of wires that communicate between the CPU and a peripheral?
bus
control
status
data

  1. How many ports are needed?
one per wire
one per group of wires
one per peripheral connection

  1. In the tape reader, what does DR=1 mean?
the tape reader has extracted a byte from the tape and placed it on data wires so the CPU can copy it into its registers
the CPU has accepted the byte and is signaling the tape reader that it can get the next byte
the tape reader is waiting to get the next byte

  1. How does the tape reader stop?
it stops after just one byte
the CPU sends it a QUERY command
the CPU sends it a HALT command

  1. What are the operands to the IN instruction?
the register where the data will be store
the port number where the data will come from
a status number

  1. When the CPU explicitly and repeatedly asks a device what its status is, we say it is...
polling
stalling
statusing
cycling

  1. In the program below, which instructions actually get a data byte and save it into main memory? 
           1.              LDI  "001b"
           2.              OUT  1
           3.  CHECKCTL:   IN   0
           4.              SUB  "01b"
           5.              JNZ  CHECKCTL
           6.              IN   2
           7.              STD  X
           8.              LDI  "11b"
           9.              OUT  0
          10.              JMP  CHECKCTL
8 and 9
1 and 2
3 and 4
6 and 7