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Computer. I/O Devices. RAM (memory). Central Processing Unit (CPU). Registers. Secondary Storage. Computer Architecture. Input devices: keyboard mouse Output devices: screen printer. Computer. I/O Devices. RAM (memory). Central Processing Unit (CPU). Registers.
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Computer I/O Devices RAM (memory) Central Processing Unit (CPU) Registers Secondary Storage Computer Architecture • Input devices: • keyboard • mouse • Output devices: • screen • printer
Computer I/O Devices RAM (memory) Central Processing Unit (CPU) Registers Secondary Storage Central Processing Unit (CPU) • Has 2 components to execute program instructions • Arithmetic/Logic Unit performs arithmetic operations, and makes logical comparisons. • Control Unit controls the order in which your program instructions are executed. • A typical CPU today can execute millions of arithmetic operations in a second.
Computer I/O Devices RAM (memory) Central Processing Unit (CPU) Registers Secondary Storage Main Memory • Sometimes called random access memory (RAM). • Stores the numbers (data) that a program uses when it runs on the computer. • Contains millions of circuits which are either off or on (0 or 1) Binary • Also stores the instructions of the program that is running on the computer. Data Program Instructions
Computer I/O Devices RAM (memory) Central Processing Unit (CPU) Registers Secondary Storage Secondary Storage • Permanent storage used to save data and programs when they are not running on the computer. • Secondary storage is cheaper per Megabyte than memory, but access to data is muchslower
Memory • The basic unit of Memory is bit. • The bit is 0 or 1. • How many bits form a memory cell ? This depends on the manufacturer but they have standardized on 8bits (1byte). • Converting from binary to decimal ? And from decimal to binary ? 1001=1*23+0*22+0*21+1*20 = 9 10010011= ? • With one bit we can have 2 values 0 or 1. List all the values that you can form with 2 bits and 3 bits ? • List the following in order of smallest to largest : byte, bit, WAN, main memory, memorry cell, LAN, secondary storage.
Exercises • What do u think that the 3 high level statements mean ? x=a+b+c; x=y*z; and z=z+1 • What is the difference between high level language and machine language ? And what system program makes the translation ? • Explain the differences among the source program, the object program and executable program ? Which one do you create ? Which one does the compiler create ? And which one does the loader or the linker create ? • Would a syntax error be found in a source program or an object program ? • What system program that would find a syntax error ? What system program that would you use to correct it ?
Other Exercises • What is the correct order of the operations : execution, translation, linking , and loading ? • How is a high level program saved on a disk ? • Before linking, how is a machine language saved on a disk ? And after ? • Which software that would control interaction of user and computer hardware ? • What does it mean booting a computer ? • What makes the difference between ROM and RAM ? • Provide the difference between a main memory and secondary storage in terms of characteristics ? (access, cost, volatility, CPU usage). • Example of WAN ? • What is a modem ?