Modern Operating Systems by Herbert Bos ...
Modern_Operating_Systems_by_Herbert_Bos_and_Andrew_S._Tanenbaum_4th_Ed.pdf-M ODERN O PERATING S YSTEMS
Showing 464 out of 1137
Modern Operating Systems by Herbert...
Modern_Operating_Systems_by_Herbert_Bos_and_Andrew_S._Tanenbaum_4th_Ed.pdf-M ODERN O PERATING S YSTEMS
##### Page 464
CHAP. 5
PROBLEMS
433
39.
A system simulates multiple clocks by chaining all pending clock requests together as
shown in Fig. 5-30. Suppose the current time is 5000 and there are pending clock re-
quests for time 5008, 5012, 5015, 5029, and 5037. Show the values of Clock header,
Current time, and Next signal at times 5000, 5005, and 5013. Suppose a new (pending)
signal arrives at time 5017 for 5033. Show the values of Clock header, Current time
and Next signal at time 5023.
40.
Many versions of UNIX use an unsigned 32-bit integer to keep track of the time as the
number of seconds since the origin of time. When will these systems wrap around
(year and month)?
Do you expect this to actually happen?
41.
A bitmap terminal contains 1600 by 1200 pixels. To scroll a window, the CPU (or
controller) must move all the lines of text upward by copying their bits from one part
of the video RAM to another.
If a particular window is 80 lines high by 80 characters
wide (6400 characters, total), and a character’s box is 8 pixels wide by 16 pixels high,
how long does it take to scroll the whole window at a copying rate of 50 nsec per byte?
If all lines are 80 characters long, what is the equivalent baud rate of the terminal?
Putting a character on the screen takes 5
μ
sec. How many lines per second can be dis-
played?
42.
After receiving a DEL (SIGINT) character, the display driver discards all output cur-
rently queued for that display. Why?
43.
A user at a terminal issues a command to an editor to delete the word on line 5 occupy-
ing character positions 7 through and including 12.
Assuming the cursor is not on line
5 when the command is given, what ANSI escape sequence should the editor emit to
delete the word?
44.
The designers of a computer system expected that the mouse could be moved at a max-
imum rate of 20 cm/sec.
If a mickey is 0.1 mm and each mouse message is 3 bytes,
what is the maximum data rate of the mouse assuming that each mickey is reported
separately?
45.
The primary additive colors are red, green, and blue, which means that any color can
be constructed from a linear superposition of these colors.
Is it possible that someone
could have a color photograph that cannot be represented using full 24-bit color?
46.
One way to place a character on a bitmapped screen is to use
BitBlt
from a font table.
Assume that a particular font uses characters that are 16
×
24 pixels in true RGB color.
(a) How much font table space does each character take?
(b) If copying a byte takes 100 nsec, including overhead, what is the output rate to the
screen in characters/sec?
47.
Assuming that it takes 2 nsec to copy a byte, how much time does it take to completely
rewrite the screen of an 80 character
×
25 line text mode memory-mapped screen?
×
768 pixel graphics screen with 24-bit color?
48.
In Fig. 5-36 there is a class to
RegisterClass
.
In the corresponding X Window code, in
Fig. 5-34, there is no such call or anything like it. Why not?
49.
In the text we gave an example of how to draw a rectangle on the screen using the Win-
dows GDI:

Browse thousands of Study Materials & Solutions from your Favorite Schools
Concordia University
Concordia_University
School:
Operating_Systems
Course:
Great resource for chem class. Had all the past labs and assignments
Leland P.
Santa Clara University
Introducing Study Plan
Using AI Tools to Help you understand and remember your course concepts better and faster than any other resource.
Find the best videos to learn every concept in that course from Youtube and Tiktok without searching.
Save All Relavent Videos & Materials and access anytime and anywhere
Prepare Smart and Guarantee better grades