1
Q
system software
A
- software that provides services that are commonly useful, including operating systems, compilers, loaders, and assemblers
- sit between hardware and applications software on hierarchy
2
Q
operating system
A
- interfaces between a user’s program and the hardware and provides a variety of services and supervisory functions
- type of systems software
- manages the resources of a computer for the benefit of the programs on that computer
3
Q
compiler
A
- A program that translates high-level language statements into assembly language statements
- makes it into instructions the hardware can execute
4
Q
binary numbers
A
- the computer language as numbers in base 2
- electrical signals of 0 or 1 (off or on) are used to speak directly to electronic hardware
5
Q
binary digit/bit
A
One of the two numbers in base 2 (0 or 1) that are the components of information
6
Q
instruction
A
- A command that computer hardware understands and obeys
- just collections of bits that computer understands
- can be thought of as numbers
7
Q
assembler
A
- A program that translates a symbolic version of instructions into the binary version
- ex. taking ADD A, B and making it a bit string
8
Q
assembly language
A
- A symbolic representation of machine instructions
- ex. ADD X1, X2, X3
9
Q
machine language
A
- A binary representation of machine instructions
- this is the language the machine runs and understands
- ex. 101000
10
Q
most important functions of an operating system
A
- Handling basic input and output operations
- Allocating storage and memory
- Providing for protected sharing of the computer among multiple applications using it simultaneously
11
Q
benefits of high level languages (4 things)
A
- can use more natural language (English, algebra)
- allow languages to be designed for intended use
- increase productively by using less lines for commands
- allow programs to be independent of the computer
12
Q
organization of computer with five classic components
A
- input, output, memory, datapath, and control
- sometime the last two are combined and called the processor
- every piece of a computer is one of these
13
Q
integrated circuit/chip
A
- usually abbreviated as IC
- A device combining dozens to millions of transistors
- there are many types of ICs
14
Q
central processor unit/processor
A
- usually abbreviated as CPU
- The active part of the computer, which contains the datapath and control and which adds numbers, tests numbers, signals I/O devices to activate, and so on
15
Q
datapath
A
The component of the processor that performs arithmetic operations
16
Q
control
A
The component of the processor that commands the datapath, memory, and I/O devices according to the instructions of the program
17
Q
memory
A
The storage area in which programs are kept when they are running and that contains the data needed by the running programs
18
Q
dynamic random access memory (DRAM)
A
- Memory built as an integrated circuit
- it provides random access to any location
- where most memory is stored
- dense and cheap, slower than SRAM
19
Q
cache memory
A
- A small, fast memory that acts as a buffer for a slower, larger memory
- built using SRAM but is NOT SRAM
20
Q
static random access memory (SRAM)
A
- memory built as an integrated circuit
-but faster and less dense than DRAM - more expensive than DRAM
21
Q
instruction set architecture/architecture
A
- An abstract interface between the hardware and the lowest-level software that encompasses all the information necessary to write a machine language program that will run correctly
- enables a machine language program to run on different hardware implementations
22
Q
application binary interface (ABI)
A
- The user portion of the instruction set plus the operating system interfaces used by application programmers
- defines a standard for binary portability across computers
23
Q
implementation
A
- hardware that obeys the architecture abstraction
- abstract interface enables many implementations of varying cost and performance to run identical software
24
Q
volatile memory
A
Storage, such as DRAM, that retains data only if it is receiving power
25
nonvolatile memory
A form of memory that retains data even in the absence of a power source and that is used to store programs between runs
26
main memory/primary memory
- memory used to hold programs while they are running
- typically consists of DRAM in today's computers
27
secondary memory
- nonvolatile memory used to store programs and data between runs
- typically consists of flash memory in PMDs and magnetic disks in servers
28
magnetic disk/hard disk
A form of nonvolatile secondary memory composed of rotating platters coated with a magnetic recording material
29
flash memory
- a nonvolatile semiconductor memory
- cheaper and slower than DRAM but more expensive per bit and faster than magnetic disks
30
transistor
An on/off switch controlled by an electric signal
31
silicon
- A natural element that is a semiconductor
- very common element
- can be transformed to be more/less conductive or both like a switch
32
semiconductor
A substance that does not conduct electricity well
33
chip manufacturing process (4 steps)
- wafers are put through 20-40 steps to make patterned wafers
- they get tested and good parts of them are marked
- wafers are diced into dies
- good dies are bonded into packages and tested again
34
how to determine what computer has better performance
- define what you consider better performance since there are many factors
- choose based off of that
35
response time/execution time
The total time required for the computer to complete a task, including disk accesses, memory accesses, I/O activities. etc.
36
throughput/bandwidth
- Another measure of performance, it is the number of tasks completed per unit time
- good way to decide what is fastest
37
how to relate performance of computer x with computer y
performance x / performance y = n
"x is n times faster than n"
- if x is n times as fast, then execution time of Y is n times as long as X
execution y / execution x = n
38
time
- the measure of computer performance
- computer that performs same amount of work in least time is fastest
39
wall clock time/response time/elapsed time
the total time to complete a task, including disk accesses, memory accesses, input/output (I/O), etc.
40
CPU execution time/CPU time
the total time the CPU spends running instructions either of a task or of the operating system for a task
41
user CPU time
- The CPU time spent in a program itself
- sub amount of the CPU time
42
system CPU time
the CPU time spent in the operating system performing tasks on behalf of the program
43
system performance
refers to elapsed time on an unloaded system
44
CPU performance
refers to user CPU time
45
clock cycle
- Also called tick, clock tick, clock period, clock, or cycle
- The time for one clock period, usually of the processor clock, which runs at a constant rate
46
clock rate
- the inverse of the clock period
- basically frequency
47
clock period
The length of each clock cycle
48
clock cycles per instruction (CPI)
Average number of clock cycles per instruction for a program or program fragment
49
instruction count
The number of instructions executed by the program
50
instruction mix
A measure of the dynamic frequency of instructions across one or many programs
51
how to represent performance of one computer quantitatively
performance = 1 / execution time
52
in measuring performance, __ is better
bigger
53
how execution time relates to clock cycles formula
execution time = CPU clock cycles for a program * clock cycle time
OR
execution = clock cycles / clock rate
54
how much is one GHz?
10^9 cycles/second
55
classic CPU equation
CPU time =
(instruction count * CPI) / clock rate
OR
CPU time = instruction count * CPI * clock cycle time
56
units for CPU execution time for a program
seconds for a program
57
units for instruction count
instructions executed for a program
58
units for clock cycles per instruction (CPI)
average number of clock cycles per instruction
59
units for clock cycle
seconds per clock cycle
60
trend in microprocessors
- shipping microprocessors with multiple processors per chip
- focus on throughput rather than execution time
- this is because individual performance of processor has slowed over time
61
power and processors
- as power grew, hard to keep electronics cool, so slowed processor performance growth
CS250
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