Category : Various Text files
Archive   : ARCHQUIZ.ZIP
Filename : ARCHQUIZ.TXT

From: [email protected] (Mark Robert Thorson)
Newsgroups: comp.arch
Subject: Test Your Comp.Arch IQ

1. When you send a control-E to a Model 33 teletype, it:

a) performs a carriage return and two line feeds
b) dumps a mechanical ROM onto its transmit channel
c) disengages the clutch between main drive shaft and keyboard
d) backspaces to the nearest tab column
e) advances the paper tape by twelve inches

2. Why did Tektronix software send control-J's in abundance
to Textronix storage tube displays?

a) clear the screen
b) enter line-drawing mode
c) parity error reset -- used to unstick terminals with parity on
d) padding character (does nothing except eat time)
e) read the thumbwheel settings

3. Tom Farrin is famous for a hack he did to DEC's pdp-11/70.
This was a trace cut and jump inside the CPU which:

a) increased the system clock speed by 12.5%
b) enabled IEEE-compatible floating-point arithmetic
c) froze the contents of the cache
d) disabled the Unibus reset that occurs automatically on a bus error
e) made separate instruction and data space available in user mode

4. As designed, the Illiac IV supercomputer was to be a 256 x 256
array of high-performance computers. What were the array
dimensions as built?

a) 64 x 64
b) 256 x 256
c) 16 x 256
d) 1024 x 1024
e) 100 x 100

5. Seymour Cray wrote the Chippewa operating system for the first
Cray's in what language?

a) Lisp
b) C
c) Fortran IV
d) assembly language
e) machine code

6. During the 1970's, IBM wasted a huge amount of money pursuing
what high-performance computing technology?

a) fluidics (based on liquid helium)
b) gallium arsenide logic
c) Josephson junctions
d) silicon-on-sapphire ECL
e) hardware execution of COBOL

7. When the 8080 microprocessor does a reference to its 256-byte
I/O address space, eight of the 16 address lines carry the I/O
address. What do the other eight address lines carry?

a) another copy of the I/O address
b) an inverted copy of the I/O address
c) undefined, reserved by Intel
d) states in the flags register
e) states for the corresponding byte in the I/O permission bit map

8. Data General lost a big lawsuit against Fairchild Semiconductor
concerning:

a) copyright on the instruction set of the Nova minicomputer
b) copyright on the microcode of the Nova minicomputer
c) mysterious fire at plant making Nova-compatible memory boards
d) Fairchild's use of the name "MDS" for their development systems
e) fraudulent labelling of untested parts as Mil-Spec

9. Magnetic bubbles were a technology for making dense, serial-
access memory chips, which passed into oblivion about 10 years ago.
Which of the following companies did NOT make a major investment
in magnetic bubble technology?

a) Intel
b) AMD
c) National Semiconductor
d) IBM
e) Rockwell

10. The ASCII rubout character is 1111111 because:

a) it is used as a flag for uninitialized data (all one's in DRAM)
b) all one's punches out all the holes on a paper tape
c) this was last character to be assigned, all other codes were used
d) the concept of "rubout" in Eastern mysticism is unity
e) Bill Gate's favorite number is 1111111

----------------------------------------------

ANSWERS:

1-B, 2-D, 3-E, 4-A, 5-E, 6-C, 7-A, 8-A, 9-B, 10-B

From: [email protected] (Mark Robert Thorson)
Newsgroups: comp.arch
Subject: Re: Test Your Comp.Arch IQ
Date: Sun, 23 Jan 94 18:29:23 PST

I didn't do a very good job on one of the questions. Here's an e-mail
I received:

------------------- begin quoted text -----------------------------

From: [email protected] (Robert Herndon)
Message-Id: <9401230943.AA17243@copper>
To: [email protected]
Subject: Re: Tst Your Comp.Arch IQ

Hi!

I enjoyed your quiz, but feel that one answer is somewhat misleading
(or maybe just over-simplified?). Your question:

3. Tom Farrin is famous for a hack he did to DEC's pdp-11/70.
This was a trace cut and jump inside the CPU which:

a) increased the system clock speed by 12.5%
b) enabled IEEE-compatible floating-point arithmetic
c) froze the contents of the cache
d) disabled the Unibus reset that occurs automatically on a bus error
e) made separate instruction and data space available in user mode

and the answer is listed as "E". I was present at a lecture he gave at
the 1978 Unix Users Group Conference in NYC (this was just before they
asked BTL for official permission to call themselves this, and were turned
down, after which the conferences became "Usenix" conferences). In it, he
described how he needed the MFPI instruction (move from previous instruction
space; it gets a word of data from the "previous mode"'s instruction space)
in order to efficiently determine the number of arguments pushed on the
stack.

This was because his lisp interpreter was too big to run without running
in separate I & D spaces (type 411 binary, as opposed to 407 (unshareable),
or 410 (shareable, but common address space). Running programs in separate
I & D spaces was an everyday event on PDP-11s at the time, but separate I&D
binaries could not use the nargs() procedure (which looked at the caller's
instructions).

Since his program was running in separate I & D spaces, any loads to
look at the caller's instructions would simply load a word from the data
space at the same address. DEC, in their wisdom, had made the MFPI and
MFPD instructions privileged, so he couldn't use them to look at his
instruction space. So he made a system call available to do this function,
but found that it was very slow. And as he put it, that wasn't very
satisfactory, and "Well, there's this NAND gate, and if you cut this
wire...", and the room dissolved in laughter. And then he told us that
this cut was available as a DEC field mod and gave us its number...

----
If you want another bit of trivia in this vein, the 407 header number
for Unix binaries is an artifact of the PDP-11's instruction set. This
is a 'branch forward 7 words'. In case you installed your block-zero
bootstrap without first stripping off the eight-word header, this allowed
it to run anyway (since the code was position independent). Other machines
have used 407 headers ever since for no good reason...

Keep up the good work!
Robert "Bring back Version 6 Unix!" Herndon