计算机概论琐碎知识点
Why are binary numbers important in computing?
Data and instructions are represented in binary inside the
computer.
A.Number
B. Natural number
C. Integer number
D. Negative number
E. Rational number
1. A unit of an abstract mathematical system subject to the laws
of arithmetic.
A
2. A natural number, a negative of a natural number, or zero.
C
3. The number zero and any number obtained by repeatedly
adding one to it.
B
4. An integer or the quotient of two integers (division by zero
excluded).
E
5. A value less than zero, with a sign opposite to its positive
counterpart.
D
.
A. True
B. False
12. Binary numbers are important in computing because a binary
number can be converted into every other base.
B
13. Binary numbers can be read off in hexadecimal but not in
octal.
B
14. Starting from left to right, every grouping of four binary digits
can be read as one hexadecimal digit.
B
15. A byte is made up of six binary digits.
B
16. Two hexadecimal digits can be stored in one byte.
A
17. Reading octal digits off as binary produces the same result
whether read from right to left or left to right.
A
46. How many ones are there in the number AB98 in base 13?
((13 * 13 * 13 * 10) + (13 * 13 * 11) + 13 * 9) + 8) = 23954
1. Lossless compression means the data can be retrieved with-
out losing any of the original information.
A
2. A computer represents information in an analog form.
B
3. A computer must use the binary number system to represent
information.
B
4. A digital signal represents one of two values at any point in
time.
A
5. Four bits can be used to represent 32 unique things.
B
6. The signed-magnitude representation of numbers has two
representations for zero.
A
7. Overflow occurs when the value that we compute cannot fit
into the number of bits we have allocated for the result.
A
8. In the ASCII character set, there is no distinction made
between uppercase and lowercase letters.
B
9. The Unicode character set includes all of the characters in
the ASCII character set.
A
10. Keyword encoding replaces frequently used words with a sin-
gle character.
A
11. Run-length encoding is very good at compressing English
text.
B
12. Huffman encoding uses variable-length binary strings to rep-
resent characters.
A
13. An audio signal is digitized by sampling it at regular intervals.
A
14. A CD stores audio information in a binary format.
A
15. The MP3 audio format discards information that can’t be
heard by humans.
A
16. An RGB value represents a color using three numeric values.
A
17. Indexed color increases the number of colors that can be
used in an image, and thus increases the file size.
B
18. Bitmap, GIF, and JPEG are all examples of raster-graphics
formats.
A
19. Vector graphics represent images in terms of lines and geo-
metric shapes.
A
20. A keyframe is used in temporal compression to represent the
changes from one frame to another.
B
1 8 23
1 11 52
•例2-11 写出十进制数5.75的单精度(余127码)表示法。
| S[1] |
E[8] |
M[23] |
| 0 |
10000001 |
01110000000000000000000 |
| Decimal |
Excess_127 |
Excess_128 |
| +25 |
1001 1000 |
1001 1001 |
| -25 |
0110 0100 |
0110 0101 |
SRAM :根据电子器件的双稳态原理来存储信息。在不断电的情况下，信息不会丢失，不需要刷新。功耗大、集成度低，运行速度比DRAM快，一般用作Cache。
DRAM：使用电容充电原理来存储信息。由于电容会漏电，所以必须对立面信息定期更新才不会丢失信息。功耗小，集成度高，用作主存。
Database
A structured set of data
Database Management System (DBMS)
A combination of software and data, made up of a physical database, a database engine, and a database schema
Physical Database
A collection of files that contain the data
Database Engine
Software that supports access to and modification of the database contents
Database Schema
A specification of the logical structure of the data stored in the database
Database Query
A request to retrieve data from a database
Relational DBMS
A DBMS in which the data items and the relationships among them are organized into tables
Table
A collection of records
Record (object, entity)
A collection of related fields that make up a single database entry
Field (attributes)
A single value in a database record