Topic 6 - Computer systems - Complete Flashcards
Define software?
Refers to the program or coded instructions that make the computer run,
Define hardware?
Refers to the physical part that makes up a computer system.
Define system software?
Is needed to carry out the tasks to operate the hardware.
Define application software?
Is needed to help carry out user-related tasks, such as Word processing, Payroll & air traffic control.
What are the 4 features of system software? O L U P
- Operating system
- Library programs
- Utility programs
- Programming language translators
What are the 3 types of application software?
G
S
B
- General-purpose (GP)
- Specialised applications (SA)
- Bespoke applications (BA)
What are some features of the operating system (OS)?
Controls the hardware and hides the complexity of the hardware by creating a platform to run application software.
What are some features of library programs?
Are pre-written software that is stored in compiled format and can be included by the programmer within one or more programs.
What are some features of Utility programs?
Are a range of system software that is designed to help the user to manage, maintain and optimise the system.
Disk formatting, file compression, data synchronisation, firewall, memory testing and anti-virus protection.
What are some features of programming language translators?
Used to translate a program in one programming language into a different programming language and to maintain the functionality of the original code.
Define these 3 types of translators?
Assembler
Compiler
Interpreter
Assembler - Used for assembly language programs
Compiler - Used for program languages like C++, Visual
Interpreter – Used for program languages like python
Define machine code?
Is the set of binary instructions that are used by the CPU to perform a task. Is processor dependant.
Define assembly language?
Is a low-level programming language which is processor-dependant, each instruction is one machine code operation.
Define high-level languages?
Is a computer programming language based on natural language or mathematical notation.
C++, Python, Java
Define declarative?
high-level languages are also based on natural language and are used to declare the necessary information to produce the required result.
Define imperative language?
Program statements or instructions are executed in a sequence or order as defined by the programmer. High-level languages are imperative.
Define the advantages of low-level language (machine code & assembly language) compared to high-level language?
Programming in low-level code can create faster and more efficient code as the programmer controls the performance level of the created code. More memory efficient.
What are the advantages of high-level languages?
It is difficult to learn to program in low-level languages whereas high-level languages have more support and training options. Easier to debug.
Define source code?
Is the language instructions that have been written by the computer programmer. The computer cannot execute the source code directly.
Define object code?
Is translated from the source code using an assembler or compiler into instructions that can be executed by the compiler.
Define assemblers?
Series of memorable mnemonics used to represent machine operational code. Assembly code is the most difficult language to program and needs a high degree of expertise to write and debug it.
What are the pros and cons of assemblers?
Pros: An efficient low-level language that can be translated quickly as it has a one-to-one relationship with machine code.
Cons: It is complex to write and takes lots of programming time and expensive
Define compilers?
The compiler converts the source code to an object, which the computer can run. Source code created by the programmer is not understandable by the computer.
What are the pros and cons of compilers?
Pros: An executable file is produced which runs without the need of the source code. This makes the source code more secure as it does not need to be distributed to the customer.
Cons: Complication of a large program takes a long time to complete and any errors in the source code need to be corrected before an executable file can be made.
Define intermediate language?
Some compilers create a final output in an intermediate language such as bytecode. The output is designed to run on a virtual machine rather than on a central processing unit.
Define Interpreters?
Interpreter software normally executes the source code directly, it is translated line by line, this avoids the need to compile the program.
Define a logic gate?
Are circuits that are used to perform a logical operation in computing and electronics
Define a truth table?
Is a diagram that shows all possible logical inputs and their associated outputs.
What are the 3 main logic gates?
NOT
AND
OR
What are the 3 other logic gates?
XOR
NAND
NOR
Define the NOT gate?
The output is opposite the input
One input & output
Define the AND gate?
Two or more inputs where the output is true if all the inputs are true
Define the Or gate?
Two or more inputs where the output is true if either or both inputs are true.
Define the XOR gate?
Two or more inputs where the output is true ONLY if one input is exclusively true
Define the NAND gate?
Two or more inputs where the output is false when all inputs are true
Define the NOR gate?
Two or more inputs where the output is true when all inputs are false
Define half adder logic?
Hald adder circuits carries out addition on two numbers (A and B) only.
Sum - A XOR B
Carry - A AND B
Define full adder logic?
Full adder circuits carries out addition on two numbers (A and B) and a carry bit.
A series of full adders can be used to add binary numbers, as the carry bit is available at each stage of the calculation.
Define a flip flop?
Is an electronic circuit that has two stable states and can be used as a memory device to store one bit of data
Define a D-type flip flop?
Changes the state with each clock pulse, so data is delayed by one clock pulse
Define Boolean expressions?
Are used in computer programs, when these expressions are evaluated they give a boolean logic output of either True or False.
What does each symbol mean?
+
.
Ā
+ Or
. AND
Ā NOT
State the 8 AND logic identities? 1.A 0.A A.A A.Ā A.B A.(B.C) A+(B.C) A.(A+B)
1.A=A
0.A=0
A.A=A
A.Ā=0
A.B=B.A
A.(B.C)=(A.B).C
A+(B.C)=(A.B).(A+C)
A.(A+B)=A
State the 8 OR logic identities? 0+A 1+A A+A A+Ā A+B A+(B+C) A.(B+C) A+(A.B)
0+A=A 1+A=1 A+A=A A+Ā=1 A+B=B+A A+(B+C)=(A+B)+.C A.(B+C)=(A.B)+(A.C) A+(A.B)=A
Define Dr Morgan’s Law?
Change all AND operators to OR
Change all OR operators to AND
Change the logical state of each variable
