computer systems Flashcards
what is hardware?
anything that physically makes up the computer
what is software?
any program or operating information that runs on or is used by the computer
what is the notation for the NOT gate?
an overbar
—–
what is the notation for the AND gate?
a dot above .
what is the notation for the OR gate?
a plus +
what is the notation for the XOR gate?
⊕
write a truth table for an AND gate with two inputs
0 0 - 0
0 1 - 0
1 0 - 0
1 1 - 1
write a truth table for an OR gate with two inputs?
0 0 - 0
0 1 - 1
1 0 - 1
1 1 - 1
write a truth table for an XOR gate with two inputs
0 0 - 0
0 1 - 0
1 0 - 0
1 1 - 1
write a truth table for an OR gate with two inputs?
0 0 - 0
0 1 - 1
1 0 - 1
1 1 - 1
write a truth table for an NOT gate with one input?
0 - 1
1 - 0
what is system software and some examples?
programs needed for the computer to function
- utilities
- operating system
- library routines
- programming language translators
what is application software and some examples?
programs that enable a user to do a task
- games
- a spreadsheet
- word processor
- web browser
what five things does the os manage?
- processor
- memory
- input / output devices
- applications
- security
what are some advantages of high-level languages?
easier to read
easier to learn
what does the os do, regarding memory?
- manages the computer’s memory
- it can control which parts of the memory are being used for each process
what does the os do, regarding processing?
- manages the computer’s processor(s)CPU;
- Schedules which processes are to be executed;
what does the os do, regarding applications?
Control access to applications;
- Prevent users or processes using unauthorised programs // allow users or
processes to use authorised programs;
- Control application access;
- Prevent/allow an application access to data (or devices);
what does the os do, regarding security?
User authentication;
- To make sure that users must prove who they are to access the system;
- Protect against malware;
- Block access to specific vulnerable operations or system areas. For
example, software can only be installed with admin access;
what does the os do, regarding input /output devices?
- manages input/output devices
- Interacts with/manages/handles the (automatic) installation of device
drivers; - Handles peripheral device interrupts;
- the computer can communicate with the outside world;
- Control network communication;
- Allow devices to send and receive data;
what is primary storage?
the memory areas that the CPU can access directly: registers, cache, ROM and RAM
what is secondary storage?
isn’t directly accessible by the cpu ( where all data is stored that is not in use
what is the volatility and speed of primary storage compared to secondary storage?
primary is mostly volatile ( needs power to be stored ( will delete when the device is turned off )
and also faster to read and write
advantages of magnetic hards disks
high-capacity
reliable
cheap
why is secondary storage required?
for long term non - volatile storage
to store data
and to transfer data to another device
advantages of solid state drives
fast read and write speeds
reliable
lower power usage
light
advantages of optical discs
cheap
portable / easy to transport
robust
disadvantages of magnetic hard disks
not very portable
can be corrupted by a magnetic field
can break easily
disadvantages of solid state drives
expensive
slightly lower capacity than hdds
begin to deteriorate / shorter read and write life
disadvantages of optical discs
easily scratched
low capacity
very slow read and write speeds
