Saturday, February 23, 2013






kilobyte (KB)



control unit

machine cycle

Operation code


data mining

machine language




massively parallel

parallel processing

arithmetic and logic unit


processing (MPP)

primary storage


encoding system

megabit (Mb)

Program register


execution time (E-time)

megabyte (MB)

programmable read


flash memory

megahertz (MHz)

only memory (PROM)



memory dump


bubble memory





gigabyte (GB)

neural network

secondary storage

cache memory


nondestructive read

terabyte (TB)

central processing unit

instruction register

nonvolatile memory

volatile memory


instruction time (I-time)




kilobit (Kb)


1- Data Storage: Data ill the Computer

Data, not information, are stored in a com­puter system. Data are stored temporarily during processing in primary storage (RAM) and permanently on secondary storage de­vices, such as magnetic tape and disk drives.

2- A Bit about the Bit The two electronic

states of the computer--on and off-are represented by a bit, short for binary digit.

These electronic states are compatible with the binary numbering system. Letters and decimal numbers are translated into bits for storage and processing on computer systems

3- Encoding Systems: Combining Bits to Form Bytes

Alphanumeric (alpha and numeric) characters are represented in com­puter storage by (combining strings of bits to form unique bit configurations for each char­acter. Character-, are translated into these bit configurations, also called bytes, according to a particular coding scheme, called an en­coding system. Popular encoding systems include ASCII and ASCII-8 .

4- Numbering Systems and Computers

The two primary numbering systems used in conjunction with computers lire binary and decimal. Decimal is translated into binary on input and binary is translated into decimal on output. The hexadecimal numbering system is used primarily as a programmer convenience in reading and reviewing binary out­put in the form of a memory dump. The octal numbering system has a base of 8.

5- Components of a Computer System: A Closer Look at the Processor and RAM

The processor is the "intelligence" of a com­puter system. A processor, which is also called the central processing unit or CPU, has only two fundamental sections, the con­trol unit and the arithmetic and logic unit, which work together with RAM to exe­cute programs. The control unit interprets in­structions and directs the arithmetic and logic unit to perform computation and logic operations .

RAM, or random-access memory, provides the processor with temporary storage for pro­grams and data. Input/output (I/O) is "read to" or "written from" RAM over a channel. In RAM, datum is stored at a specific ad­dress. Most of today's computers use CMOS technology for RAM. CMOS is volatile mem­ory; that is. the data are lost when the electrical current is turned off or interrupted. In contrast, bubble memory provides non­volatile memory. All input/output, includ­ing programs. must enter and exit RAM. Pro­grams are loaded to RAA from secondary storage in a nondestructive read process. Other variations of internal storage are ROM,PROM, and flash memory.

Some computers employ cache memory to increase throughput. Like RAM. cache is a high-speed holding area for program instructions and data. however cache memory holds only those instructions and data likely to he needed next by the processor. During execution, instructions and data arc passed between very high-speed registers (for ex­ample, the instruction register, program register, and the accumulator) in the con­trol unit and the arithmetic logic unit

Every machine language has a prede­fined formal for each type of instruction. Each instruction has an operation code (op-­code) and an operand During one ma­chine cycle, an instruction is "fetched" from RAM, decoded by the decoder in the control unit, executed. and tire results are placed in memory. The machine cycle time is the total of the instruction lime (I-time) and the ex­ecution time (E-time).

Most mainframes and PCs use else (com­plex instruction set computer) architecture Those using RISC (reduced instruction set computer) architecture realize increased throughput for certain applications.

In parallel processing, one main proces­sor examines the programming problem and determines what portions, if any, of the prob­lem can be solved in pieces. Those pieces that can be addressed separately are routed to other processor . solved, then recombined in the main processor to produce the result Parallel processing on a large scale is referred to as massively parallel processing (MPP).

Neural network-designed computers mimic the human mind. When perfected. are expected to excel at human-oriented tasks such as pattern recognition and reading handwriting .

6- Describing the Processor: Distinguishing Characteristics

A processor is de­scribed in terms of its word length. speed. and RAM capacity. The word (the number of bits handled as a unit) length of computers ranges from 16 hits for the smaller micros to range bits for more powerful computers. Micro­computer speed is measured in megahertz (MHz). Workstation. mini, and mainframe speed is measured in MIPS. Supercomputer speed is measured in FLOPS and GFLOPS. memory capacity is measured in kilobytes (KB), megabytes (MB), gigabytes (GB). and terabytes (TB). Chip capacity is sometimes stated in kilobits (Kb) and megabits (Mb).



1. Distinguish between RAM, ROM and PROM.

2. How many ASCII-S bytes can be stored in a 32-bit word?

3 . Which two functions are performed by the arithmetic and logic unit?

4. List examples of alpha, numeric, and al­phanumeric characters.

5. Write your first name as an ASCII hit con­figuration.

6. What are the functions of the control Unit?

7. we describe computers in terms of what three characteristics ?

8. what are the binary and hexadecimal equivalents of a decimal 12?

9. What is the baste difference between CMOS technology and nonvolatile technology , such as bubble memory?

10. For a given computer. which type of mem­ory would have the greatest capacity to store data and programs: cache or RAM? RAM or registers? registers or cache

11. Name three types of registers

12. Which portion of the fundamental computer purer instruction designates the operation to be performed?

13. Which type of computer architecture has the smaller instruction set, RISC or CISC?

14. The I and the E in I-time and E-time stand for what?


15. KB is used to represent 1024 bytes of stor­age. Would it have been much easier to let KB represent 1000 bytes? Explain.

16. If neural networks realize their potential. the distinction between what have tradi­tionally been human-oriented tasks and machine-oriented tasks may begin to blur. Should society be doing anything that we are not already doing to prepare for this? Explain.

Problem Solving

17. Create a five-bit encoding system to be used for storing uppercase alpha charac­ters, punctuation symbols, and the apostro­phe. Discuss the advantages and disadvan­tages of your encoding system in relation to the ASCII encoding system

18. Compute the time it takes to complete one cycle on a 66-MHz processor in both sec­onds and nanoseconds.

19. Convert 5 MB to KB, Mb, and Kb. Assume a byte contains eight bits.

20. Complete a numbering-system table that shows the binary, octal, and hexadecimal equivalents for the decimal numbers 1 through 20.

ELF-TEST (by section]

1- Data are stored permanently on secondary storage devices, such as magnetic tape. (T/F)

2- a. Bit is the singular of byte, (T/F)

b. The base of the binary number system is: (a) 2, (b) 8, or (c) 16?

3- The combination of bits used to represent a character is called a -

4- a. A is a "snapshot" of the contents of RAM at a given moment in time.

When you count in hexadecimal, you carry to the next position in groups of

5- a. Data are loaded from secondary to RAM in a nondestructive read process. (T/F)

b. The is that part of the processor that reads and interprets program instruc­tions.

c. The arithmetic and logic unit controls the flow of programs and data In and out of main memory. (T/F)

d. Put the following memories in order based on speed: cache, registers, and RAM,

e. The timed interval that comprises the machine cycle is the total of the time and the time.

6- a. The word length of most microcomputers is 64 bits. (T/F)

b. MIPS is an acronym for "millions of in­structions per second." (T/F)

c. is a common measure of super computer processor speed

Self-test answers. 1 T. 2 (a) F; (b) a. 3 byte. 4 (a) memory dump; (b)16.5 (a) T, (b) control unit; (c) F; (d) from the slowest to the fastest memory' RAM, cache, registers; (e) instruction, execution 6 (a) F; (b) r, (c) FLOPS or GFLOPS.