6: Fundamentals of Computer Systems Flashcards
1
Q
Hardware
A
The physical components of a computer system
2
Q
Software
A
Instructions / code / programs
3
Q
System Software
A
Software used in the management of a computer system
4
Q
Application Software
A
Software for carrying out user-oriented tasks
5
Q
Operating System (3)
A
- Provides a user interface between the user and the hardware
- Runs application programs
- Manages resources / hardware
6
Q
Utility Program (1, 1:4)
A
- Programs designed to help maintain the computer
- Examples include:
• Virus scanner
• Disk defragmenter
• System monitor
• File managers
7
Q
Library Program (2)
A
- Are collections of resources used to develop software
- Include pre-written code and subroutines
8
Q
Translators (4)
A
- Convert source code into machine code
- Assembler converts assembly code into machine code
- Compiler converts source code written in a high-level language into machine code
- Interpreter treats high level language source code as data and interprets that data as instructions to its own routine
9
Q
Examples of System Software (4)
A
- Operating systems (OSs)
- Utility programs
- Libraries
- Translators (compilers, assemblers, interpreters)
10
Q
The operating system hides ____
A
The complexities of the hardware
11
Q
OS Functions (8)
A
- To hide the complexities of the hardware from the user
- To call appropriate interrupt handler when an interrupt occurs
- To allocate processors to processes
- To allocate memory to processes
- To allocate I/O devices to processes
- To allocate space on a storage device to files
- Installation of new software and managing updating software
- Manage power consumption
12
Q
Classification of Programming Languages (2)
A
- Low-level languages: are based upon the instruction set of the computer
- High-level languages: are problem-oriented and close to a natural language
13
Q
Low-Level Languages (2)
A
- Machine-code
- Assembly language
14
Q
High-level languages include ____
A
Imperative high-level language
15
Q
Machine-Code Language
A
Is written in binary and doesn’t require translation to be run
16
Q
Assembly Language
A
Help programmers write machine-code using a set of ‘mnemonics’, that represent a binary, machine-code statement
17
Q
Low-Level Languages + (4)
A
- Programs give better access to computer hardware
- Programs may execute more quickly as they require less translation
- Some programs can only be written using a low-level language particularly some parts of a computer’s operating system
- Programs may use less memory
18
Q
High-Level Languages + (8)
A
- Programs are portable
- Program code is easier to understand
- Faster development time
- Availability of flow control structures
- Improved features for supporting modularity
- Built-in support for data structures
- Language is problem-oriented
- Support for different paradigms
19
Q
Imperative High-Level Language (4, 1:4)
A
- Instructions are executed in a programmer-defined order
- Imperative languages describe how to solve a problem
- High-level languages use English-like keywords
- They support structured statements
- They support the use of:
• Local variables
• Parameters
• Named constants
• Indentation
20
Q
One statement in an imperative high-level language corresponds to ____
A
Many low-level language statements
21
Q
Compilation +/- (4)
A
+ Commercial software is compiled before distribution to protect the source code
- Errors are reported at the end of compilation, which makes debugging harder
+ Object code runs very quickly but programs take long to compile
+ Users don’t need a translator to run object code
22
Q
Interpretation +/- (4)
A
+ Developers can quickly test the program without having to translate the entire program every time
+ Errors appear as they occur so it is easy to identify and fix them
- Interpreting source code is slower than running object code
- Users must have a translator to run the source code
23
Q
Intermediate Language (3)
A
- Some compilers produce an intermediate language (e.g., bytecode) as their final output
- This is because the code may need to run on multiple platforms
- To execute it, a virtual machine performs just in time translation to convert the intermediate language to object code and execute it
24
Q
Source Code vs Object (Executable) Code
A
Source code is code in its original form, written by the programmer whereas object code is compiled source code, which can be executed
25
Logic Gates (6)
- NOT
- AND
- OR
- XOR
- NAND
- NOR
26
Truth Table for NOT Logic Gate
Input | Output
0 | 1
1 | 0
27
Truth Table for AND Logic Gate
Input | Input | Output
0 | 0 | 0
0 | 1 | 0
1 | 0 | 0
1 | 1 | 1
28
Truth Table for OR Logic Gate
Input | Input | Output
0 | 0 | 0
0 | 1 | 1
1 | 0 | 1
1 | 1 | 1
29
Truth Table for XOR Logic Gate
Input | Input | Output
0 | 0 | 0
0 | 1 | 1
1 | 0 | 1
1 | 1 | 0
30
Truth Table for NAND Logic Gate
Input | Input | Output
0 | 0 | 1
0 | 1 | 1
1 | 0 | 1
1 | 1 | 0
31
Truth Table for NOR Logic Gate
Input | Input | Output
0 | 0 | 1
0 | 1 | 0
1 | 0 | 0
1 | 1 | 0
32
Diagram for NOT Logic Gate
https://isaaccomputerscience.org/api/v2.19.3/api/images/content/computer_science/computer_systems/boolean_logic/figures/sys_bool_logic_gates_not.svg
33
Diagram for AND Logic Gate
https://isaaccomputerscience.org/api/v2.19.3/api/images/content/computer_science/computer_systems/boolean_logic/figures/sys_bool_logic_gates_and.svg
34
Diagram for OR Logic Gate
https://isaaccomputerscience.org/api/v2.19.3/api/images/content/computer_science/computer_systems/boolean_logic/figures/sys_bool_logic_gates_or.svg
35
Diagram for XOR Logic Gate
https://isaaccomputerscience.org/api/v2.19.3/api/images/content/computer_science/computer_systems/boolean_logic/figures/sys_bool_logic_gates_xor.svg
36
Diagram for NAND Logic Gate
https://isaaccomputerscience.org/api/v2.19.3/api/images/content/computer_science/computer_systems/boolean_logic/figures/sys_bool_truth_tables_nand2_2.svg
37
Diagram for NOR Logic Gate
https://isaaccomputerscience.org/api/v2.19.3/api/images/content/computer_science/computer_systems/boolean_logic/figures/sys_bool_truth_tables_nor2_labelled.svg
38
Boolean Expressions (6)
- A AND B = A ⋅ B
- A OR B = A + B
- NOT A = ̅A
- A NAND B = ̅A ̅⋅ ̅B
- A NOR B = ̅A ̅+ ̅B
- A XOR B = A ⊕ B
39
____ can be Used to Simplify Simple Boolean Expressions
Truth tables
40
Boolean Identities (5)
- Commutative law
- Associative law
- Absorption law
- Distributive law
- De Morgan's law
41
Commutative Law
AND: A ⋅ B = B ⋅ A
OR: A + B = B + A
42
Associative Law
AND: (A ⋅ B) ⋅ C = A ⋅ (B ⋅ C)
OR: (A + B) + C = A + (B + C)
43
Absorption Law
AND: A ⋅ (A + B) = A
OR: A + (A ⋅ B) = A
44
Distributive Law
AND: A + (B ⋅ C) = (A + B) ⋅ (A + C)
OR: A ⋅ (B + C) = (A ⋅ B) + (A ⋅ C)
45
De Morgan's Law
AND: ̅A ̅⋅ ̅B = ̅A + ̅B
OR: ̅A ̅+ ̅B = ̅A ⋅ ̅B
46
Order of Boolean Operations (4)
- Brackets (first)
- NOT
- AND
- OR
47
Compilation vs Interpretation (6)
- A compiler produces object code whilst an interpreter does not
- A compiler translates the whole of the source code into object code whilst an interpreter translates line by line
- The object code produced by a compiler will execute faster, than interpreting the source code
- An interpreter can run parts of a program whilst there are syntax errors in other parts of it, which a compiler cannot
- Once code has been compiled it does not need to be recompiled whilst an interpreter has to translate code every time a program is run
- If using an interpreter, it needs the source code each time it executes the program whereas a compiler only needs to use the source code once
48
Binary Half-Adder Circuit
https://isaaccomputerscience.org/api/v3.1.6/api/images/content/computer_science/computer_systems/boolean_logic/figures/isaac_cs_sys_bool_binary_half_adder.svg
49
https://isaaccomputerscience.org/api/v3.1.6/api/images/content/computer_science/computer_systems/boolean_logic/figures/isaac_cs_sys_bool_binary_full_adder.svg
Binary Full-Adder Circuit
50
Edge Triggered D-Type Flip-Flop (3)
- This is used as a NAND flash memory unit
- On the rising edge of each clock signal, the state of the data input is accepted and the output is updated to reflect this
- Once the clock signal input goes low, the state of the circuit will not change and store the output
51
OS Processor Management (2)
* To allocate processors to processes
* Schedule processes
52
OS Memory Management (4)
* To allocate memory to processes
* To determine what areas of memory
are used for what purpose
* Moving data into and out of RAM / to a paging file for virtual memory
* Ensuring processes can only write to memory that they have been allocated
53
OS I/O Devices Management (3)
* To allocate I/O devices to processes
* Manages communication between
processes and I/O devices
* Automatic installation of drivers for new I/O devices
54
OS Storage Management (4)
* To allocate space on a storage device to files
* Organising files into directories
* Determines where on a device to save a file
* Recognising storage devices when
they are connected
