IGCSE- Computer science (1)

Advantages of serial data transmission.

-more accurate/fewer errors over a longer distance -less expensive wiring -less chance of data being skewed/out of synchronisation/order

What are the benfits of using a USB?

1. The connectors can only fit one way; this prevents incorrect connections being made 2. This has become the industry standard; this means that considerable support is available to users 3. Supports multiple data transmission speeds

What are the disadvantages of using a USB?

1. The maximum cable length is presently about 5 metres 2. The present transmission rate is limited to less than 500 megabits per second

Binary to denary

2 to the power of, add the ones at the bottom together

How many bits in a byte?

8

What is Asynchronus data transmission?

ASYNCHRONOUS DATA TRANSMISSION refers to data being transmitted in an agreed bit pattern. Data bits (1s and 0s) are grouped together and sent with CONTROL BITS

What do the last 6 characters represent in a MAC address?

DD-DD-DD represent the serial number of the device

Denary to binary

Divide by 2 each time. There's a 0 at the end.

What is a full-duplex data transmission?

FULL-DUPLEX DATA TRANSMISSION is in both directions simultaneously. Example: broadband connection on a phone line.

What is half-duplex data transmission?

HALF-DUPLEX DATA TRANSMISSION is in both directions but not at the same time. Example: a phone conversation between two people where only one person speaks at a time.

Storage in order

Kilobyte Megabyte Gigabyte Terabyte Petabyte

What do the first 6 characters represent in a MAC address?

NN-NN-NN represent the identity number of the manufacturer

Parallel data transmission.

PARALLEL DATA TRANSMISSION is when several bits of data (usually 1 byte) are sent down several wires or channels at the same time.

Serial data transmission.

SERIAL DATA TRANSMISSION is when data is sent, one bit at a time, over a single wire or channel (bits are sent one after the other in a single stream).

What is Synchronus data transmission?

SYNCHRONOUS DATA TRANSMISSION is a continuous stream of data. The data is accompanied by timing signals generated by an internal clock. This ensures that the sender and receiver are synchronised with each other.

When is parallel data transmission used?

Sending data to a computer from a printer OR Internal data transfer

What is simplex data transmission?

Simplex data transmission goes in one direction only (i.e. from sender to receiver). Example: data being sent from a computer to a printer.

What is the '%' in a web address?

The '%' in a web address shows that a hexadecimal is being used in an ASCII code.

What is an ASCII code?

The American Standard Code for Information Interchange is represented in hex or in decimal. Can be used to represent a web address in %

What is a USB

The UNIVERSAL SERIAL BUS (USB) is an asynchronous serial data transmission method.

MAC address

Uniquely identifies a device on the internet. Made up of 48 bits. NN-NN-NN-DD-DD-DD

Types of MAC addresses, and which on is the most common?

Universally administered address (UAA-most common) and Locally administered address (LAA)

HTML

Used in processing, definition and presentation of text. Also used to represent colours of text on the computer screen.

Memory dump

When memory contents are output to a printer or monitor

When is serial data transmission used?

When you connect a computer to a modem

Advantage of parallel data transmission.

faster rate of data transmission