Unit 1.2: Understand the hardware requirements of a computer system

Printers (2D)

A peripheral which makes a persistent human-readable representation of graphics or text on paper or similar physical media. Types include lazer, inkjet etc

Pipelines

A set of data processing elements connected in series, where the output of one element is the input of the next one. The elements of a pipeline are often executed in parallel or in time-sliced fashion; in that case, some amount of buffer storage is often inserted between elements. Example: Multiplication - a programmer would have to tell the computer where the first number was, where the second number was, what operation to perform (a multiply), and then where to store the result.

parallel bus

A shared channel that transmits data over several wires simultaneously. For example, a 32-bit bus has 32 wires. PCI is a common version.

FireWire

Also called IEEE 1394, another popular connector for adding peripherals to your computer. Most often used to connect digital camcorders, external hard drives, audio interfaces and other devices that can benefit from the high transfer rates (up to 480 Mbps) supported by the connection.

AC) to (DC).

Power supplies which convert power from alternating current to direct current.

i Types of memory chips

Random Access Memory (RAM) Static Random Access Memory(SRAM) Dynamic Random Access Memory (DRAM) Read Only Memory (ROM) Programmable Read Only Memory (PROM) Erasable Programmable Read Only Memory (EPROM) Electrical Erasable Programmable Read Only Memory (EEPROM).

Biometric

Refers to metrics related to human characteristics. This authentication is used in computer science as a form of identification and access control. It is also used to identify individuals in groups that are under surveillance.

k PCIe

S high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X, and AGP bus standards. Has numerous improvements over the older standards, including higher maximum system bus data throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting, AER), provides hardware support for I/O virtualization.

System bus

Single computer bus that connects the major components of a computer system, combining the functions of a data bus to carry information, an address bus to determine where it should be sent, and a control bus to determine its operation.

Speakers

Sold for use with computers, although usually capable of other audio uses, e.g. for an MP3 player. Most have an internal amplifier and consequently require a power source, which may be by a mains power supply often via an AC adapter, batteries, or a USB port (able to supply no more than 2.5W DC, 500mA at 5V). The signal input connector is often a 3.5 mm jack plug; RCA connectors or USB port may supply both signal and power.

Extensible firmware interface (EFI)

Specification that defines a software interface between an operating system and platform firmware. Replaces the Basic Input/Output System (BIOS) firmware interface. Provides several technical advantages over a traditional BIOS system: GUI interface boot from large disks (over 2 TB)with GUID Partition CPU-independent architecture & drivers Flexible pre-OS environment, including network capability Modular design Backward and forward compatibility Provides legacy support for some motherboards./BIOSs

e The internal components of a computer

- Motherboard - CPU - RAM • Power supply units (PSUs) • fans • hard drives. • Cards or expansion cards such as sound, graphics, network cards etc. • Input/output controllers.

Accumulator

A CPU register in which intermediate arithmetic and logic results are stored.

Control unit

A component of a computer's central processing unit (CPU) that directs the operation of the processor. It tells the computer's memory, arithmetic/logic unit and input and output devices how to respond to a program's instructions.

Advanced Technology Attachment (SATA)

A computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. offers several advantages over the older interface: reduced cable size and cost, native hot swapping, faster data transfer through higher signalling rates, more efficient data transfer through an (optional) I/O queuing protocol.

Screens (monitors)

A computer display is an electronic visual display for computers. Usually comprises the display device, circuitry, casing, and power supply . The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) or a flat panel LED display. It can be connected to the computer via VGA, DVI, HDMI, DisplayPort, Thunderbolt or other proprietary connectors and signals.

USB flash drive

A data storage device that includes flash memory with an integrated USB interface. Typically removable and rewritable, and physically much smaller than an optical disc. Most weigh less than 30 grams. Storage capacities have risen while prices have dropped( 8GB to 2TB) Storage capacities as large as 4 TB are planned, with steady improvements in size and price per capacity expected. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and have a 10-year shelf storage time.

hard disk drives

A data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (platters) coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces.Data is accessed in a random-access manner, meaning that individual blocks of data can be stored or retrieved in any order and not only sequentially. A type of non-volatile memory, retaining stored data even when powered off.

Scanner

A device that optically scans images, printed text, handwriting or an object and converts it to a digital image. Commonly used in offices are variations of the desktop flatbed - where the document is placed on a glass window for scanning. Hand-held versions, where the device is moved by hand, have evolved from text scanning "wands" to 3D versions used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven versions that move the document are typically used for large-format documents, where a flatbed design would be impractical.

Arithmetic logic unit (ALU)

A digital circuit used to perform arithmetic and logic operations. It represents the fundamental building block of the central processing unit (CPU).

Input/output controllers

A family of microchips (southbridge) used to manage data communications between a CPU and a motherboard, designed to be paired with the northbridge.

Optical disks

A flat, circular disc which encodes binary data (bits) in the form of pits (binary 0, due to lack of reflection when read) and lands (binary 1). Encoding pattern follows a spiral path covering the entire disc surface & extending from the innermost to the outermost track. Data is stored on the disc with a laser and can be accessed when the data path is illuminated with a laser diode in a disc drive which spins the disc at speeds of about 4,000 RPM or more, depending on the drive type, disc format etc Designed to support one of three recording types: read-only (e.g.: CD and CD-ROM), recordable (write-once, e.g. CD-R), or re-recordable (rewritable, e.g. CD-RW).

Main memory (RAM)

A form of volatile data storage which stores frequently used instructions to increase the speed of processing. RAM allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory.

non-maskable interrupts (NMI)

A hardware interrupt that lacks an associated bit-mask, so that it can never be ignored. Used for the highest priority tasks such as timers. (Has to happen).

d Maskable interrupts (IRQ)

A hardware interrupt that may be ignored by setting a bit in an interrupt mask register's (IMR) bit-mask (denied by the CPU).

c The effect and purpose of an interrupt on a Fetch-Execute Cycle

A signal to the CPU emitted by hardware or software indicating an event that needs immediate attention. Alerts the CPU to a high-priority condition requiring the interruption of the current code the CPU is executing (FDE). The CPU responds by suspending its current FDE activities, saving its state, and executing a function called an interrupt handler (or interrupt service routine (ISR) to deal with the event. This interruption is temporary, and, after the interrupt handler finishes, the processor resumes normal activities.

system bus

A single computer bus that connects the major components of a computer system, combining the functions of a data bus to carry information, an address bus to determine where it should be sent, and a control bus to determine its operation.

Multi-core processors

A single computing component with two or more independent actual processing units (called "cores"), which are units that read and execute program instructions (Running the FDE cycle).

Registers

A small high speed memory locations that are part of the computer processor to hold instructions during the FDE cycle. May hold an specific instruction, storage address, depending on its purpose within the FDE cycle.

solid state drive (SSD)

A solid-state storage device that uses integrated circuit assemblies as memory to store data persistently. Primarily uses electronic interfaces compatible with traditional block input/output (I/O) hard disk drives (HDDs), which permit simple replacements in common applications. Has no moving mechanical components. This distinguishes them from traditional electromechanical magnetic disks such as hard disk drives (HDDs) which contain spinning disks and movable read/write heads. Typically more resistant to physical shock, run silently, have lower access time, and lower latency.

memory bus

A type of computer bus, usually in the form of a set of wires or conductors which connects electrical components and allow transfers of data and addresses from the main memory to the central processing unit (CPU) or a memory controller.

Erasable Programmable Read Only Memory (EPROM)

A type of programmable read-only memory that can be erased and re-used. Erasure is caused by shining an intense ultraviolet light through a window that is designed into the memory chip.

Dynamic Random Access Memory (DRAM)

A type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1.

Programmable Read Only Memory (PROM)

A type of read-only memory ( ROM ) that can be modified once by a user. Is a way of allowing a user to tailor a microcode program using a special machine. This machine supplies an electrical current to specific cells in the chip that effectively blows a fuse in them.

Video or Graphics card

Also called a display card) is an expansion card which generates a feed of output images to a display (such as a computer monitor). Frequently, these are advertised as discrete or dedicated graphics cards, emphasising the distinction between these and integrated graphics. The GPU is responsible for rendering an image to your monitor much faster than a CPU. A simple way to understand the difference between a GPU and a CPU is to compare how they process tasks. A CPU consists of a few cores optimised for sequential serial processing while a GPU has a massively parallel architecture consisting of thousands of smaller, more efficient cores designed for handling multiple tasks simultaneously.

Printers (3D)

Also known as additive manufacturing (AM), refers to processes used to synthesize a three-dimensional object, in which successive layers of material are formed under computer control to create an object. Objects can be of almost any shape or geometry and are produced using digital model data from a 3D model or another electronic data source such as an Additive Manufacturing File (AMF) file.

data bus

Also known as internal bus, memory bus or Front-Side-Bus, connects all the internal components of a computer, such as CPU and memory, to the motherboard. Internal data buses are also referred to as a local bus, because they are intended to connect to local devices.

Cooperative multitasking

Also known as non-preemptive multitasking, is a style of computer multitasking in which the operating system currently controlling the CPU must offer control to other processes. It is called cooperative because all programs must cooperate for it to work. If one program does not cooperate, it can hog the CPU.

Bar code reader

An electronic device that can read and output printed barcodes to a computer. Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones. Nearly all contain decoder circuitry analysing the barcode's image data provided by the sensor and sending the barcode's content to the scanner's output port.

Universal Serial Bus (USB)

An industry standard that defines the cables, connectors and communications protocols used in a bus for connection, communication, and power supply between computers and electronic devices. Designed to standardise the connection of computer peripherals (including keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters) to personal computers, both to communicate and to supply electric power. It has become commonplace on other devices, such as smartphones, PDAs and video game consoles. It has effectively replaced a variety of earlier interfaces, such as parallel ports, as well as separate power chargers for portable devices.

Sound or audio card

An internal expansion card that provides input and output of audio signals to and from a computer under control of computer programs. Also applied to external audio interfaces used for professional audio applications. Uses include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education and entertainment (games). Functionality can also be integrated onto the motherboard.

projector

An optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most create an image by shining a light through a small transparent lens, but some newer types can project the image directly, by using lasers.

Electrical Erasable Programmable Read Only Memory (EEPROM).

Another type of programmable read-only memory that can be erased and re-programmed using a pulsed voltage.

a The internal components of a CPU including their purpose

Arithmetic logic unit (ALU). • Main memory. • Cache. • Control unit. • Registers; • Accumulator • Pipelines. • Multi-core processors.

Retinal scanner

Biometric technique that uses the unique patterns on a person's retina blood vessels. Advantage Low occurrence of false positives low (almost 0%) false negative rates Reliable - no 2 people with same pattern Speedy results: Quick verification Disadvantages Accuracy can be affected by eye diseases Scanning is perceived by some as invasive Not very user friendly scanned eye must be close to the camera High equipment cost

Serial

Connector by which a device that sends data one bit at a time may be connected to a computer.

m Internal bus

Connects all the internal components of a computer, such as CPU and memory, to the motherboard. Also referred to as a local bus, because they are intended to connect to local devices. This bus is typically rather quick and is independent of the rest of the computer operations.

b The steps of the Fetch-Execute Cycle

Fetch/retrieve/open instruction/command from memory/RAM CPU stores instructions in its (temporary) registers Decode instruction/command / decide what to do (or other reference to data processing) Execute/run instruction/command

BIOS boot order

First to loads up, checks CMOS settings Initialises devices Runs POST (checks hardware components) BEEPS once if everything's ok or beeps error code! Checks for boot-able drive with OS If no boot partition or loader, looks on next drive for OS Loads the OS off whatever drive it finds

finger scanner

Hardware for the automated method of verifying a match between two human fingerprints. This is one of many forms of biometrics used to identify individuals and verify their identity.

Static Random Access Memory (SRAM)

Is a type of random access memory (RAM) that retains data bits in its memory as long as power is being supplied. Unlike dynamic RAM (DRAM), which stores bits in cells consisting of a capacitor and a transistor but does not have to be periodically refreshed.

j Basic input output system (BIOS) and and purpose

Is the the program on a motherboards ROM chip used to get the computer system started after you turn it on, independent from the operating system. Instructions carried out include booting computer, identification of components and devices via power on self-test (post), loading the OS from a boot-able drive. It also manages data flow between the computer's operating system and attached devices such as the hard disk, video adaptor, keyboard, mouse and printer.

External bus

Made up of the electronic pathways that connect the different external devices, such USB(universal serial bus) for printers etc.

Read Only Memory (ROM)

Once data has been written onto a the chip, it cannot be removed and can only be read. Unlike main memory (RAM), it retains its contents even when the computer is turned off. It is referred to as being nonvolatile, whereas RAM is volatile.

q The purpose of specialist operator consoles

Other names include: system console, computer console, root console, operator's console. A physical device consisting of a keyboard and a screen, and traditionally is a text terminal, but may also be a graphical terminal. Allow text entry and display device for: system administration messages generalised computation virtual consoles and terminal emulators. Today communication with system consoles is generally done abstractly, via the standard streams (stdin, stdout, and stderr), but there may be system-specific interfaces. Specialist versions are seen in a wide range of industries for specialists tasks, usually requiring unique hardware configurations (input output) as well as construction, application and features.

serial bus.

The process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels. Serial computer buses are becoming more common even at shorter distances, as improved signal integrity and transmission speeds in newer serial technologies have begun to outweigh the parallel bus's advantage of simplicity.

Data bus

This contains the contents that have been read from the memory location or are to be written into the memory location.

Address bus

This determines the location in memory that the processor will read data from or write data to.

Control bus

This manages the information flow between components indicating whether the operation is a read or a write and ensuring that the operation happens at the right time.

h How internal hard drives work

Typically has only one platter, but each side of it has a magnetic coating. Bigger versions have a series of platters stacked on a central spindle, with a small gap in between them. The platters rotate at up to 10,000 revolutions per minute (rpm) so the read-write heads can access any part of them.

Computer ports

Universal Serial Bus (USB), FireWire, Serial

Cache

Used by the CPU to reduce the average cost (time) to access data from the main memory. The cache is a smaller, faster memory which stores copies of frequently used instructions or data from main memory locations.

Preemptive multitasking

When the operating system uses some criteria to decide how long to allocate to any one task before giving another task a turn to use the operating system. The act of taking control of the operating system from one task and giving it to another task is called preempting.

p Secondary/backing storage

hard disk drives, USB drives, read/writeable DVDs, removable magnetic disks, fixed magnetic disks, solid state drives (SSD)

n Input devices

mouse, scanner, keyboard, touch screen, web cam, microphone, barcode reader, sensors.

Network card

network adapter is a computer hardware component that connects a computer to a computer network. Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus. The low cost and ubiquity of the Ethernet standard means that most newer computers have a network interface built into the motherboard. Modern network interface controllers offer advanced features such as interrupt and DMA interfaces to the host processors, support for multiple receive and transmit queues, partitioning into multiple logical interfaces, and on-controller network traffic processing such as the TCP offload engine.

o External output devices

printers (2D, 3D), screens, speakers, slide projectors

k Input/output controllers & expansion cards such as sound, graphics, network cards etc. & their purpose

• Cards or expansion cards such as sound, graphics, network cards etc.

f Internal and external power supply units (PSUs)

• Power supply units (PSUs)

g Cooling devices and their purpose

• fans: • heat sinks and thermal paste: • water-based: