Computer Neek

Memory Management, Processor Scheduling, Backing store Management, Peripheral Management / I/O Management.

Allocates time slices for different applications.

Contains bootstrap information that is loaded up when the computer starts.

2 bits.

3 bits.

At least one input must be true for the output to be true else the output is false.

The input has to a be a false for the output to be true and the for the output to be false the input must be a true.

So that software can't be reversed engineered to find the source code.

When programmers specify what instructions are and are written in our language.

A + B

Number of bits transmitted per second over a wired or wireless data link.

Rate at which the signal communication channel changes state.

If both inputs are true then the result is false, otherwise the result is true.

Translators are used to convert high level programming languages into low level programming languages.

Compiler, Interpreter, Assembler

Executes line by line and stops when there is an error, hence making it easier to debug. Analysing is quick.

Execution time is longer.

Allows for complex jobs to be easier. Memory efficient as it requires less memory. Its fast as execution time is small. It also has a one-to-one correspondence between machine code instruction.

Both inputs have to be false for the output to be true otherwise the output is false.

Compiler saves machine code so source code is no longer necessary. Compilers are Quick to execute as code is already compiled. Since code is compiled it doesn't take much memory to store.

Errors aren't usually spotted until a program is run. Also, the compiled code is hardware specific as different platforms have different binary code.

Utility software, Translators, Library Programs and thes OS.

General system, Special purpose, Bespoke Software.

Back-up Software

Interpreter

Word processor

A payroll System

Different combinations of the NAND gate can act like a NOT, OR and AND gate.

Reduces production costs, reduces heat produces, reduces energy requirement, increases the speed of a circuit.

Utility software is designed to analyse, configure, optimise or maintain a computer system.

A program that manages a computer's resources.

Windows

Defragmentation, install/uninstall software, virus checker, keep software up to date.

It's tailored for the client making it more user friendly and efficient. Client also has control over the software.

More expensive as companies have to cover all costs. It takes time to produce.

Only one input must be true for the output to return true, otherwise the output is false.

A ⊕ B

Keeps track of the value of data which is captured and committed to memory at a specific moment in time.

Only changes in the rising of the edge of the clock signal which is when it changes from 0 to 1.

8 bits

4 bits

2^4 = 16. 16 different colour combinations.

The portion of the instruction that specifies the operation that needs to be performed.

Data or address used to operate the instruction.

When data and instruction are stored in the same memory location

The Von Neumann architecture

(Colour depth x Height x Width) / 8

Height x Width

Height x Width

Images created using a sequence of commands or mathematical statements.

They are scalable which ensures consistent quality if the image is enlarged. Modification on a small scale is easier. Supports layering in graphics packages.

A small error in a vector graphic graphic is obvious if the image is enlarged. They can't display detailed image properties like a bitmap image.

When checking if bits have been corrupted by the interface during transmission and that they have been received.

Checks if there is an error in a sequence of bits

It is shorter and easier to remember as well as easier to read.

Information about images that is stored within the image itself.

Commands for the computer

When the operand of the instruction refers directly to a location in memory.

In the general purpose registers

Solid with no moving parts. Almost twice as fast as loading up and copying files than HDD. They are also silent.

Lazer beams etches pits which represents the binary number 0 and the lands(the areas that have not been etched on) represents the number 1

It's only able to hold a limited amount of information

It can encode more complex data.

Decodes the 1D or 2D barcode

Laser is reflected of a moving mirror allowing the barcode to be read in many different positions.

The barcode emits a laser light and detects the reflected light off the barcode. The white columns reflect laser light which corresponds to a 0 and the black columns do not reflect light which corresponds to a 1.

It helps to determine which way round the scanner has to read the barcode.

The diode in the pen measures the light intensity that is reflected back. This generates a wave form. The dark coulombs absorb light and the white coulombs reflect it. The wave form is then translated into a digital format.

They are normal numbers we use to count.

sequence of numbers in a numerical or alphabetical order.

Numbers that can be put into a fraction

Numbers that can't be put in a fraction

Numbers that are both rational and irrational

Composed of blocks of pixels making it easy to edit. It's easy to compress a bitmap image into a smaller size

File size can be very large. Not scalable as quality degrades when zoomed in.

The Analogue signal sampled at regular intervals reference to a graph. The amplitude of the wave is measured. The measurement is coded into a fixed number of bits.

There is greater scrutiny on the code. Other programmers can learn from the code.

Produces high quality images.

Uses more power than a CMOS sensor

Uses much less power than a CCD sensor

Uses much less power than a CCD sensor

A powered receiver emits a radio signal. The transponder the object then becomes energised by the radio waves. The transponder can now send data to the receiver.

An underflow is when a maths operation result smaller than what the device is capable of storing.

An overflow is when a maths operation result is larger than what the device is capable of storing.

Symmetric ciphers is when the same key is used.

The key is truly random and that the key is used only once and then destroyed.

Because the metadata will also be stored in the image.

A mosaic of red, green and blue filters are placed . The software then makes digital approximations in binary for each individual pixel based on the values of neighbouring pixels.

The number of cycles that a processor carries per second

The greater the clock speed increases the number of operations that can be processed thus the faster the computer will run.

The CPU can get too hot.

Fetches, decodes and executes instructions and performs logical and arithmetic operations.

The data and the control bus.

A thicker bus width means greater amounts of addresses, data and signals can be sent.

It's cheap per GB of storage and is portable.

It's easy to break/scratch. It has slow read/write speeds.

Cheap per GB of storage. It has medium read/write speed. It also has a high capacity of storage,

Not very portable and can be damaged if dropped. It will slow down eventually if files get fragmented.

Moore's Law states that the number of transistors on a processor doubles about every 2 years.

A physical limit will be reached where there will be so many transistors that they produce too much heat.

Because processing power is being taken up by moving data around rather than executing instructions.

Conducts heat which allows the fan to blow it away.

The unique identifier on a NIC.

The switch stores all the MAC addresses for all the devices and directs the data to the device with that mac address.

Havards's CPU is faster as you can receive data and instructions due to them each having their own memory. This also makes Havard's CPU more expensive. Von Numman's CPU is error prone as data and instruction can be mistaken for each other.

To store frequently used data and instructions.

A temporary volatile memory space created when RAM is full.

Stores arithmetic and logic operations.

Regulates and integrates the operations of the computer.

Short-term register that stores arithmetic and logic operations.

Holds the address of the next instruction to be processed.

Millions of transistors are either on or off and remain so until electricity is applied to the system. SSD's use switches called floating gate transistors. These create a special cage that traps the electron flow within it. This gate effect continues whether there is electricity in the system or not and so storage remains when power is removed.

It has more storage capacity. Magnetic hard drives are also cheaper per unit storage than SSD. Data can also be overwritten directly onto the disk with magnetic hard drive.

Controller, NAND gate and flash memory.

More expensive per GB.

It allows for more instructions to be carried out in parallel.

It increases the amount of data and instructions that are frequently used which decreases latency and increases performance.

It increases the speed of which RAM transfers information to other components.

Current instruction register.

Cd drive shines a laser onto the surface of the disk and detects the reflective areas and bumps by the amount of laser they reflect. The drive converts reflections into 0 and 1's.

bits in synchronous communications are scheduled whilst bits in asynchronous communication happen on its own time and do not need scheduling.

0

1

It's quicker as its closer to the CPU meaning that it takes less time for data to reach it.

Primary storage contents are not saved when the computer is off. Secondary storage contents are loaded up when the computer is switched on.

To check whether a software or hardware requires attention.

The program counter(PC) copies its contents to the MAR(Memory address register). The PC then increments by 1 and holds the address of the next instruction. The processor sends a signal to the MAR via the address bus. From there its contents are copied to the MBR via the data bus. Its contents are then copied to the CIR ready for it to be decoded. From there the instruction is decoded and executed. The CIR monitors and manages the whole process.

Hardware and software interrupts.

First normal form(1NF), second normal form(2NF) and third normal form(3NF)

It simplifies the data structure. It also reduces data redundancy and removes repeating data. It also makes it easy to update, remove and search data. It reduces the size of a database.

A flat file is one big table of data whilst relational databases have many tables of data linked together.

Not all the data is needed at the same time. It also takes too much time to search and is prone to spelling mistakes.

There is no duplicate data, less data is stored making it smaller in size and its less prone to spelling errors.

An technique used to ensure that transactions don't overlap in time.

The method only allows one transaction at a time from multiple connected clients

Every transaction will have a timestamp when it starts. The timestamp protocol orders the transactions based on the oldest protocole first.

The same transactions will have priorities over others according to their dependencies as well as timestamp.

When a user saves an update , if the read timestamp is not the same as it was when they started the transaction, the database management system (DBMS) knows another users has accessed the same object.

The consistency of the database is maintained as only one copy is held. Access rights and security are managed centrally and backup and recovery are managed centrally.

Simultaneous requests can cause the server to crash. The server is also a point of failure.

It is 1NF if it contains no repeating attributes or groups of attributes.

Locks records from modification and only allows records to be modified by one client at a time and unlocks after client is done.

This ensures that no transactions are lost if 2 clients simultaneously try to update a record.