FACTORS THAT DETERMINE THE TYPE OF COMPUTER TO CHOOSE1) Type of processor (Central processing unit – CPU)
Microcomputers use microprocessors, which are manufactured on a single chip, as their CPU.
In larger computers such as supercomputers, mainframe & minicomputers, the processing is carried out by a number of separate, high-speed components instead of a single processor. 2) Processing speed.3) Amount of Main memory (RAM).
All computers have some amount of RAM (Random Access memory), which is used to hold the instructions required to perform a task.
Larger computers have more RAM and therefore can handle large volumes of data & also support many and sophisticated programs which might require large memory sizes. 4) Storage capacity of the Hard disk.
The storage capacity is the amount of space that is available for storing the instructions required to manipulate data.
Larger computers have higher storage capacities than microcomputers. 5) Cost of the computer.
The cost of computers is directly related to the size. Microcomputers are less costly compared to minicomputers, mainframes or Supercomputers.
6) Speed of Output devices.
The speed of an output device is determined by the amount of information that can be printed in a specified amount of time.
The speed of microcomputer output device is less than that of the larger computers in that: For a microcomputer, the speed of its output device is measured by the number of characters printed per second (cps). For larger computers, their output devices are faster and their speeds are measured depending on the number of lines or pages printed per minute (lpm / ppm). 7) Number of users who can access the computer at the same time.
Most microcomputers can support only 1, 2 or 3 users at the same time. However, they can be networked to share resources.
Larger computers can support hundreds of users at the same time. Understanding RISC AS A TYPE OF PROCESSOR
RISC is a type of processor which simply means
R - Reduced I - instruction S - Set C – Computer
When computers process, they require a microprocessor for the task, this microprocessor also requires instructions in order to operate.
The instructions are written in a language that only the computer can understand, basically in the form of binary and assembly languages coded in schemes such as ASCII – American Standard Code for Information Interchange and EBCDIC – Extended Binary Coded Decimal Interchange Code. 
Processor Architecture
The idea was to make microprocessor changes that were more independent of coding schemes since instructions require more equipment.
The more the instructions the slow the processing speed simply because more instructions require additional circuitry and transistors which makes the whole process complicated, difficult to setup, additional power consumption, rising of heat during processing and additional circuitry means more path links (buses).
In 1974 John Cocke of IBM Research in Yorktown, New York, originated the RISC concept by proving that about 20% of the instructions in a computer did 80% of the work. The term itself (RISC) is credited to David Patterson, a teacher at the University of California in Berkeley. The concept was used in Sun Microsystems' SPARC microprocessors and led to the founding of what is now MIPS Technologies (MIPS - millions of instructions per second), part of Silicon Graphics. A number of current microchips now use the RISC concept.
The first computer to benefit from this discovery was IBM's PC/XT in 1980. Later, IBM's RISC System/6000, made use of the idea.
Discovery of RISC led to a more thoughtful architecture of microprocessors such as how well an instruction can be mapped to the clock speed of the microprocessor this led to the improvement of microprocessor manufacture and design. Advantages of RISC
CategoriesJoin our Whatsapp Notifications and Newsletterstouch here COURTESY OF ATIKA SCHOOL All OUTPUT DEVICES
Output devices are those devices that play the following roles:
EXAMPLES OF OUTPUT DEVICES
CategoriesJoin our Whatsapp Notifications and Newsletterstouch here COURTESY OF ATIKA SCHOOL All EXAMPLES OF COMPUTER INPUT DEVICESINTRODUCTION
Computer input devices are those devices that perform the following functions with a computer:
EXAMPLES OF INPUT DEVICES
CategoriesJoin our Whatsapp Notifications and Newsletterstouch here COURTESY OF ATIKA SCHOOL All THE TYPES AND FUNCTIONS OF MEMORY DATA REGISTERS (MDR)INSTRUCTION REGISTER
Instruction Register Instructions register (IR) is used to store the instruction currently being executed or decoded.
ACCUMULATOR
Accumulator or An accumulator is a register for short -term . intermediate storage of arithmetic and logic data in a computer’s CPU (central processing unit).
STORAGE REGISTER
Storage Register Holds a piece of data that is on its way to and from the CPU and the main memory.
ADDRESS REGISTER
The Memory Address Register (MAR) is a CPU register that either stores the memory address from which data will be fetched to the CPU or the address to which data will be sent and stored.
CategoriesJoin our Whatsapp Notifications and Newsletterstouch here COURTESY OF ATIKA SCHOOL All DIFFERENCES BETWEEN HARD COPY AND SOFT COPY OUTPUT DEVICESOutput from the computer can normally be in several forms. Give the difference between the following methods.(2Marks)
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#
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SOFTCOPY
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HARDCOPY
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1
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it is intangible
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it is tangible
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2
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it is flexible in editing
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cannot be easily edited
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3
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does not require stationery
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requires stationery
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4
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they are cheap to produce
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they are expensive to produce
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5
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easily transmissible
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difficult to distribute
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6
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requires electrical signals to use
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after printing does not require electrical signals
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7
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has no mass
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has mass
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Categories
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All
1998
1998 KCSE
1999
APPLICATIONS AREAS OF ICT
Career Opportunities In ICT
COMPUTER SYSTEMS
DATABASE
DATA PROCESSING
DATA SECURITY AND CONTROLS
ELEMENTARY PROGRAMMING PRINCIPLES
FIELD
FILE
FORM 1
FORM 2
FORM 3
FORM 4
IMPACT OF I.C.T ON SOCIETY
INTRODUCTION TO COMPUTERS
INTRODUCTION TO NETWORKING AND DATA COMMUNICATION
KCSE 2018
KCSE QUESTIONS 1998
KCSE QUESTIONS 2007
MIND BLOWING Q & A
MOCKS
Operating System
OPERATING SYSTEMS
OUTPUT DEVICES
PROGRAM DESIGN
RECORD
REVISION KITS
SPREADSHEET
SPREADSHEETS
STORAGE DEVICES
SYSTEM DESIGN
THE COMPUTER LABORATORY
WORD PROCESSORS
GIVE TWO TYPES OF STORAGE DEVICES USED IN A COMPUTER GIVING AN EXAMPLE OF EACH.
INTRODUCTION;
- The duration they store information;
- Mobility and;
- How they function.
a) CLASSIFICATION OF STORAGE DEVICES BASED ON THE DURATION OF TIME THEY STORE INFORMATION.
- Secondary storage devices
- Primary storage devices
1. secondary storage devices
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2. primary storage devices
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b) classification of storage devices based on mobility.
- Fixed storage devices and;
- Portable storage devices
1. fixed storage devices
2. portable storage devices
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c) classification of storage device on how they function.
- Solid state storage device
- Magnetic storage device
- optical storage devices
1. solid state storage devices
2. optical storage devices
3. magnetic storage devices
|
What is a laser printer?
How a laser printer works
- Millions of bytes (characters) of data stream into the printer from your computer.
- An electronic circuit in the printer (effectively, a small computer in its own right) figures out how to print this data so it looks correct on the page.
- The electronic circuit activates the corona wire. This is a high-voltage wire that gives a static electric charge to anything nearby.
- The corona wire charges up the photoreceptor drum so the drum gains a positive charge spread uniformly across its surface.
- At the same time, the circuit activates the laser to make it draw the image of the page onto the drum. The laser beam doesn't actually move: it bounces off a moving mirror that scans it over the drum. Where the laser beam hits the drum, it erases the positive charge that was there and creates an area of negative charge instead. Gradually, an image of the entire page builds up on the drum: where the page should be white, there are areas with a positive charge; where the page should be black, there are areas of negative charge.
- An ink roller touching the photoreceptor drum coats it with tiny particles of powdered ink (toner). The toner has been given a positive electrical charge, so it sticks to the parts of the photoreceptor drum that have a negative charge (remember that opposite electrical charges attract in the same way that opposite poles of a magnet attract). No ink is attracted to the parts of the drum that have a positive charge. An inked image of the page builds up on the drum.
- A sheet of paper from a hopper on the other side of the printer feeds up toward the drum. As it moves along, the paper is given a strong positive electrical charge by another corona wire.
- When the paper moves near the drum, its positive charge attracts the negatively charged toner particles away from the drum. The image is transferred from the drum onto the paper but, for the moment, the toner particles are just resting lightly on the paper's surface.
- The inked paper passes through two hot rollers (the fuser unit). The heat and pressure from the rollers fuse the toner particles permanently into the fibers of the paper.
- The printout emerges from the side of the copier. Thanks to the fuser unit, the paper is still warm. It's literally hot off the press!
Source: EXPLAINTHATSTUFF!
RELATED LINKS ..
Advantages of laser printers
- They produce neat and high quality work
- They are fast in printing
- They are cheap to maintain
- They can print back-to-back pages (both sides of the page automatically and sequentially)
- They can print a series multiple pages
- Don't make noise while printing
- Can print both graphic and text
Read More ...
Disadvantages of laser printers
- They are expensive to acquire
- They cannot produce multiple copies output
- Their toner (ink gadget) is expensive to acquire
Additional Information ...
wHAT ARE SECONDARY sTORAGE DEVICES?
These devices can be categorized as:
Related links ..
- Removable storage media
- Magnetic storage media
- Floppy Disk
- Zip disk
- LS-120 Superdisk
- Magnetic tape
- Optical storage media
- Optical card
- Compact disk (CD)
- Digital Versatile Disk (DVD)
- Optical tape
- Solid state storage media
- Memory card
- Flash disk
- Magnetic storage media
- Fixed Storage media
- Magnetic storage media
- Examples: The hard disk (HDD)
- Magnetic storage media
DRAW A DIAGRAM SHOWING THE FUNCTIONAL UNITS OF A COMPUTER HARDWARE. NAME THE UNITS
01. INPUT DECICES
Examples of these devices include:
- Keyboard/Keypad
- Mouse
- Trackball
- Scanner
- Digitizer
- Whiteboard
- Digital camera
- Joy stick
02. Central Processing unit
- Manipulate numeric and logic data (A.L.U - Arithmetic & Logic Unit)
- Coordinate processing activities (Control Unit)
- Provide temporary storage (Registers, buffers and caches)
03. Primary Storage
- RAM - Random Access Memory
- ROM - Read Only Memory
- Logical Drives: These are hard disk partitions that behaves like a RAM once that memory in the RAM has been fully utilized.
04. Secondary Storage
- Fixed Storage Devices
- Magnetic
- The Hard Disk
- Magnetic
- Portable Storage Devices
- Solid State Storage Devices
- Memory card
- Flash Disk
- Magnetic storage devices
- Magnetic tapes
- Floppy disks
- Zip disks
- Magnetic tape
- optical storage devices
- Compact disks (CD)
- Digital Versatile Disks (DVD)
- Solid State Storage Devices
05. Output Devices
- Hard Copy
- Printer
- Plotter
- Soft Copy
- Screen/Monitor/VDU
- LED - Light Emitting Diode
- Sound Output (such as speakers)
Categories
All
1998
1998 KCSE
1999
APPLICATIONS AREAS OF ICT
Career Opportunities In ICT
CLASSIFICATION OF COMPUTERS
COMPUTER SYSTEMS
DATABASE
DATA PROCESSING
DATA SECURITY AND CONTROLS
ELEMENTARY PROGRAMMING PRINCIPLES
FIELD
FILE
FORM 1
FORM 2
FORM 3
FORM 4
IMPACT OF I.C.T ON SOCIETY
INPUT DEVICES
INTRODUCTION TO COMPUTERS
INTRODUCTION TO NETWORKING AND DATA COMMUNICATION
KCSE 2018
KCSE QUESTIONS 1998
KCSE QUESTIONS 2007
MIND BLOWING Q & A
MOCKS
Operating System
OPERATING SYSTEMS
OUTPUT DEVICES
PROCESSING DEVICES
PROCESSORS
PROGRAM DESIGN
RECORD
REGISTERS
REVISION KITS
SPREADSHEET
SPREADSHEETS
STORAGE DEVICES
SYSTEM DESIGN
THE COMPUTER LABORATORY
WORD PROCESSORS
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