What is a computer? Flashcards
What is a computer?
A general-purpose machine that processes data according to a set of instructions stored internally.
According to Patterson and Hennessy what are the five basic components of a computer system?
Input, Output, Memory, Datapath, Control
What is the classic number of computer generations?
4
Who came up with the idea of the classic number of computer generations and what year did he do this?
Tanenbaum, 1999
1st generation computer dates:
1945?-1955
1st generation computer circuitry:
Vacuum tubes
1st generation computer memory:
Magnetic drums
1st generation computer input:
Paper tape and punch cards
1st generation computer output:
Printouts
What drove computer invention?
Allied code-breaking efforts in WW2
What are two examples of early computers that drove the first generation of computers?
British COLOSSUS, American ENIAC
What language did 1st generation computers use for software?
Machine code
What was the computation time for 1st generation computers?
Milliseconds
How large were 1st generation computers?
Room-sized
What was built in 1948 at Manchester University?
1st stored program machine
What was LEO initially?
Bakery
What was famous about LEO?
First computer in the world to run an office job
What job did LEO’s computer do?
Calculated the valuation of the output from its Bakeries
What was the circuitry in 2nd generation computers?
Transistors
What five advantages over the previous generation of computers did the transistor bring?
Smaller, faster, cheaper, more reliable, more efficient
What was the main memory of 2nd generation computers?
Magnetic core
What was the secondary memory of 2nd generation computers?
Magnetic tapes and disks
What language were 2nd generation programs written in?
Assembly Language
What are two examples of high level languages that were first introduced during the 2nd generation of computers?
COBOL - COmmon Business Orientated Language
FORTRAN - FORmula TRANslator
What was the computation time for second generation computers?
Microseconds
2nd generation computer dates?
1955-1965
What generation of computers was the software industry said to be born in?
2nd
What 3 pins does a transistor have?
- Emitter
- Base
- Collecter
Which pin in the transistor acts as a switch?
Base
What direction does current flow in a transistor?
Collecter -> Emitter if voltage applied to base
What voltage generally needs to be applied to the base pin to allow a current to flow from Collecter -> Emitter?
0.7V
3rd generation computer dates?
1965-1980
3rd generation computer circuitry?
Integrated circuits
3rd generation computer circuitry benefits?
Increased computer speed and efficiency
3rd generation input norm?
Keyboards
3rd generation output norm?
Monitors
3rd generation notable introductions?
Operating systems
What generation of computers saw the introduction of operating systems?
3rd
What language are 3rd generation programs written in?
High level languages
What is 3rd generation computation time?
Nanoseconds
4th generation computer dates?
1980 - ?
What method of integration is used for computer circuitry?
Large scale integration (LSI) and very large scale integration (VLSI) is used to implement transistors
What are the benefits of 4th generation circuity?
Computer performance is increasing and size is decreasing
What is the 4th generation CPU?
A single chip - the microprocessor
What is the 4th generation main memory?
Semiconductor memory
What other storage improvements are made in the 4th generation of computers?
Magnetic disks get larger and a number of other peripherals and storage media are introduced
What modern day OSs are introduced in the 4th generation of computers?
DOS, Windows, Macintosh
What is happening to programming languages in the 4th generation of computers?
They continue to arise and evolve
What type of user interface predominates the 4th generation of computers?
Graphical user interfaces
What revolution is made around connectivity in the 4th generation of computers?
Computers become linked through networks and then the internet emerges
What are 4th generation computation times?
Picoseconds
What is an example of an early 4th generation computer?
Commodore PET (Personal electric translator)
What are some discernible features of the Commodore PET?
Green text on black background Command line interface No mouse 4-96kb memory 1 Mhz CPU
What inspiration for the computer did Charles Babbage conceptualise in 1840s?
Analytical engine
What were the 8 components of the analytical engine?
- The store (Hard disk or memory)
- The mill (CPU)
- Steam engine (Power)
- Printer (Output)
- Operation cards (program)
- Variable cards (addressing system)
- Number cards (input)
- Barrel controllers (microprograms)
What is the quote used by Ada Lovelace when she suggests that the analytical machine might be able to do more than just calculate?
“the engine might compose elaborate and scientific pieces of music”
What did Herman Hollerith create in the late 1880s
Punched cards that could be read and stored by machine
What had only been stored on machine readable mediums prior to Herman Hollerith’s invention?
Instructions (on punched cards)
What did Alan Turing conceive at Cambridge University in 1935?
The Universal Turing machine
What was the idea of the universal Turing machine?
It was an abstract computing machine with limitless memory, a scanner that moves back and forth to read symbols and write further symbols.
What concept did Claude Shannon create in 1936?
The closed and open circuit - suggesting use of binary in computers. Hence the general concept of logic gates
What is the first specific part of a computer Von Neumann describes?
CA - the central arithmetic part
What is the second specific part of a computer Von Neumann describes?
CC - the central control part
What do the CA and CC parts combined make up in the Von Neumann model?
the C
What is the third specific part of a computer Von Neumann describes?
M - the total memory
What is the fourth specific part of a computer Von Neumann describes?
I input. It will be seen that it is best to make all transfers from R (by I) into M, and never directly into C
What is the fifth specific part of a computer the Von Neumann describes?
O - output. It will be seen that it is again best to make all transfers from M (by O) into R, and never directly from C
What does R represent in the Von Neumann model?
Recording medium outside the device
What is the role of the processor (including 6 duties) as a major hardware subsystem?
Does simple calculations Makes comparions Makes decisions Transforms data Manages storage of data Manages retrieval of data
- Follows instructions stored in program
What two things do subsystems need to be in order for the hardware to function?
Controlled: by the operating system and the drivers
Interconnected: To allow communication - done by buses and defined external interfaces
What are examples of microcomputers?
Tablets, handhelds, desktops, laptops etc…
What is a minicomputer?
A multi-user server
What are the properties of a mainframe computer?
Very high numbers of users and processing
Used by big companies and banks
Other systems are connecting as clients
What are the properties of supercomputers?
Calculation intensive
Big data applications
Used by major universities and science labs
When rounded to the nearest integer, what percentage of microprocessors are in embedded devices?
100%
