Grade 11 Information Technology covers a range of foundational topics, including computer basics, architecture, operating systems, and networking. It also addresses internet basics, database management, and programming fundamentals, culminating in an introduction to software development. This summa...
IT THEORY GRADE 11 (2018)
MODULE 1.1 – HARDWARE
THE MOTHERBOARD
Large piece of circuitry board with slots and connectors that allow different components and peripherals to
connect to it.
• Provides connections for other circuits (RAM, CPU etc.)
• Ensures communications between components
• Distributes power to parts connected to it.
Modular Design
A Computer design philosophy which incorporates a variety of separate ‘modular’ components, thereby
facilitating different components and peripherals.
Modular Design makes it easy to:
• Repair the computer by replacing faulty components
• Upgrade PC by adding new parts or replacing existing parts with more powerful versions
NB for repairing and upgrading:
ZIF-socket (Zero Insertion Force) – connects A Type of socket for mounting a CPU that is designed
CPU not to stress or damage the CPU during insertion
DIMM-slots (Dual Inline Memory Module) Electronic circuit boards with RAM on it.
SATA connectors – cables connecting storage cables connecting storage devices/DVD-CD drives
External connectors (USB, VGA) Built in connectors in the motherboard – for connection at
the back of the computer.
Expansion slots (ISA, MCA, EISA, PCI, PCI-X, Used to add extra circuits to your motherboard
AGP, PCI-E
Components on the Motherboard:
CPU
The CPU (Central Processing Unit) is the part of the computer that does all the processing.
The machine cycle (simplified sequence of steps)
1. Fetching data & instructions from RAM (memory)
2. Decoding instructions
3. Executing instructions
4. Transferring data back to memory
ROM (Read Only Memory)
Permanent non-volatile memory associated with Firmware; typically found in the ROM chip, which holds the start-
up instructions (BIOS) of the computer.
• BIOS (Basic Input Output System) - Boot up
• Controls hardware at the lowest level
• Options for the user to configure
• Checks that rest of hardware is present and working (POST)
• Find OS and loads it
CMOS – (Complementary Metal Oxide Semiconductors) memory is where the BIOS settings that can be
changed are stored. The Motherboard has a small battery on it that keeps the CMOS from losing its data as the
CMOS memory will lose its data if it goes without power. This Battery also keeps the date and time clock running
when the computer is switched off.
• ROM in other devices:
• Firmware controls the basic working of a device
• E.g. The printer driver receives 2’/ “print” instruction from operating system and translates it to
an instruction that the firmware can understand
• The OS on smartphones and tablets is stored in firmware
• Upgrading Firmware
• Device can be made to function faster and get new functions
• EEPROM (Electronically Erasable Programmable Read-only Memory) is totally wiped and
replaced with an updated version (This is called flashing the ROM)
• This process must not be interrupted
• Typical types of devices that need ROM firmware upgraded: Smartphones, tablets, GPS
devices, video cards
,RAM (Memory)
▪ Temporary, volatile storage area for all running programs and data being processed
▪ Before any program can run or any data can be processed, it must be loaded onto RAM first.
▪ RAM is supplied in DIMMS (Comes in the form of small electronic boards), that fit into DIMM slots into
the motherboard.
RAM is:
• electronic – no moving parts
• fast – because it is electronic
• volatile – loses contents when power is off
• comparatively expensive – per GB
• limited by
– number memory addresses that can be accessed by OS (32 bit / 64 bit
– number of memory slots
Differences between RAM and ROM
Volatile (RAM) Non-Volatile (ROM)
Loses its contents when power is turned off (Store Does not lose contents when power is removed
data for temporary time only) (Store data permanently)
Can be read from and written to by the processor and Data is pre-recorded for read only and cannot be
other devices modified or removed
Hold data or programs that are currently being used Contain a small start-up program (BIOS) which is
by the processor used to boot the computer
RAM chip are assembled on a small circuit board Exists as a chip on the motherboard
called memory module which is plugged into memory
slots
Video Cards/Graphics Cards
Hardware component that generates the images – both graphic and text – displayed on the monitor. Either
integrated on the motherboard or supplied as a separate card plugged into a PCI-Express slot.
• Has a GPU (Graphics Processing Unit) and RAM (Memory) to work with images rendered?
• Its task is to create images(output) and display it on the monitor
• Having a GPU (Graphics Processing Unit) lessens the burden on the CPU
• Laptops have built-in/integrated video adaptor AND video card, switches between them
• DVI – VGA – S-Video – HDMI -Crossfire
DATA TRANSMISSION
The Role of the motherboard is to make sure that all the components attached to it can communicate with each
other
• How does data transmission take place?
▪ system clock controls timing of everything that happens in the computer
▪ two main types of connections (direct point-to-point and shared bus connections)
▪ Communication between devices and system
Data-Transfer
• System Clock (GHz) – a quartz crystal that vibrates at a constant frequency. All activities are
coordinated against this.
• Clock multiplication
Bus – path along which data travels
Point to point connections
• Direct and dedicated, not shared between multiple components
• CPU to RAM and CPU to graphics card
Data Transfer To peripherals via USB
• Physical connection (USB, Firewire, Thunderbolt)
• IRQ / Hardware interrupt
• Plug and play
• Device identifies itself to the Operating System
• IRQ and memory space is allocated without conflicting with other devices
• Operating System searches for a driver
• When a driver is found, it is then automatically loaded for you
Hot-Swappable - the ability to plug in or remove a device even when the power is on and computer is working,
E.g.: USB devices
Plug-and-Play - technology that automates the configuration process of a device before it can be used
, CACHING
Types of Caching
▪ CPU – The Cache can be a special type of fast memory in the CPU
▪ Storage – The cache can also be part of the normal RAM which is used to speed up access to slower
storage devices.
▪ Communications – the Cache can even be part of storage that is reserved to speed up data access in
slower communication devices.
STORAGE
Storage provides a place where a computer can keep data and instructions permanently.
Characteristics:
• Non-volatile/permanent
• Relatively slow
• Relatively cheap
• Most storage devices are mechanical – contain moving parts
• Devices such as flash drives and SSD’s use EEPROM (faster, smaller)
Types of storage
Hard drive Made of plate covered in magnetic powder to store data
Both sides of the disc there is a read and write head that can move to the outer edge to
the inner edge of the platter
Optical disks – CD
– DVD
– Blu-ray
Flash disks User a modified form of EEPROM with a specialised memory controller to store data.
Solid state disks – SSD
– Expensive
– Fast
Portable hard drives – Firewire, USB, Thunderbolt, eSATA
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