Do You Know ?

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FDISK command

Do you wish to enable large disk support (Y/N) ?

Y - FAT 32, N - FAT Type Y

Create DOS partition or logical DOS drive.
First run FDISK and format the disk, so that it can store data.

Format C:/S/V followed by Enter key formats C drive and copy the stystem files and asks for Volume label entry.

Norton Utilities can unformat a disk before writing. If an area remains unreadable after the initial read and five retries, it is marked in ther FAT as bad cluster.

Error - Invalid media type means the drive has been partitioned but not formatted.
Error - Invalid drive specification, if the drive does not have a valid partition or if the boot sector is damaged.

By Moore's law, processing speed and transistor counts are doubling every 1.5 to 2 years.

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Pentium & Cache

Pentium III Xeon (processor) with 2 MB on die-cache has 140 million transistors. Cache memory stores the frequently accessed data. Cache memory on motherboard are called L2 (level 2) Cache while that on processor is called L1 Cache - more faster than L2. Later 486 chips has on die-cache (L1 cache) and L2 cache runs at motherboard speed. Now a days L1 and L2 cache are running at processor speed. We cannot compare systems on pure MHz done because other factors affect system performance (efficiency).

Pentium 4 runs at 2.1 GHz while the motherboard speed is 400 MHz (5.25 x). The processors used today can run at different speeds depending on motherboard speeds. 2.93 GHz (Pentium IV) is the maximum speed in which we can run the processor depending on motherboard and other parameters (32/64 data bus) etc.

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Cache

Processors running at 50 MHz or faster should have a heat sink on top of them to draw away the heat. Take the heat sink and chip out of the socket to read the markings at the bottom. Additional cooling fans and heavy duty power supply are required to work at a high speed.

72 pin SIIM (Single Inline Memory Module) is 32 bit, while the DIIM (Double Inline Memory Module) is 64 bit - for Pentiun III and Celeron processors. Most processors have 32 bit internal registers, while Itanium is 64 bit.

Address bus indicates the maximum amount of RAM that a chip can address. Pentium II onwards use 32 bit address bus, with an addressing capacity of 2^32 bits (64 GB).

On latest processors the L1 cache is 64 kB and it runs at the same speed of the processor. L1 cache can be as addressed without time delay. Memory speed is expressed in ns (nano second/10^-9 s).

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Pentium IV, 1.7 GHz has L1 & L2 cache (0.6 ns) and RDRAM 2.5 ns at 800 MHz when the motherboard is at 400 MHz. Pentium uses CISC (Complex Instruction Set Computer) chips. P2/3 chips were made of SEC (Single edge contact).

Socket 370 has 370 pins for P3/ Celeron chip. Socket 603 has 603 pins for Xeon chip(P4). Chip is connected to auto VRM (Voltage Regulator Module). When one is inserting Chip on a socket by force, it can damage the motherboard hairline tracks. New chips use Zero insertion force sockets. CPU power consumption is reduced by reducing the out put
voltage from 5 V to 1.6/3.3 V.

Main motherboard destroyers are screw driver, heat sink & chips. To avoid the scratching of motherboard use a thin plastic sheet while closing the heat sink clip. Active heat sinks have fans for cooling. 12 V fan connector can be connected to motherboard sockets. When attaching a passive heat sink to processor, apply thermal transfer grease on processor for good heat transfer.

Processor 486 onwards have builtin floating pointing units. In software the Version changes, while in hardware 'steppings' happens.

Windows 95, 88 & ME are 32 bit Operating Systems, while Windows XP is 64 bit for the Itanium processor.

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Signal

Data is communicated by means of a signal, and a signal is a change in voltage over time. There are mainly two types of signals - Analog and digital. Distortion of the signal is known as interference. Examples for analog signals are human voice, AM radio (535 to 1605 kHz), FM radio (88 to 108 MHz) etc.

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IP Address

Current IP address is of 4 bytes 932 bits) and can have 4,294,467,295 addresses. IP version 6 will use 16 bytes to address in future.

The 4 byte IP addresses is of four decimal numbers separated by dots. E.g. : 134.220.198.170. Each number can be separated by a byte. E.g. : 10000110.

IP address consists of two parts - network portion and the host portion. The network portion routes packets between networks while the host portion identifies a particular device on the host network.

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There are five classes of IP addresses from A to E and each class is identified by first bit of the address. IP address is provided by Internet assigned address authority - ripe, apnic and internic.

Protocols define how devices and applications communicate. TCP/IP was developed for use on the internet for the American Department of Defence and has become the industry standard. TCP is responsible for connection oriented communication using error checking while IP - implemented in the addressing system used to identify devices.

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Backing up of data : The process of copying data stored on a computer and making an exact dupicate of that data on another storage device or FTP the data to a remote system or on a CD or DAT (Digital Audio Tape of 24 GB capacity).

Back up of data will help an easy recovery from a system crash. A company's data is more valuable than it's hardware. It is inexpensive to store large amount of data at off site storage (to protect data from natural disasters, theft, viruses, worms etc).

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Microprocessor

Depending on the motherboard speed, the processor speed will vary. e.g. : With 33 MHz motherboard speed, a DX 4 processor will run at 100 MHz. If motherboard speed is 16 MHz , the DX 4 will run at 48 MHz.

On 19 Oct 1992, Intel released the V th generation chip - Pentium. It uses superscalar technology - have the capability to execute two instructions at the same time using twin data pipelines. Thus Pentium is like two 486 chips under the hood. Pentium second generation released in 1994 runs at 200 MHz, 32 bit register, 64 bit data bus, 4 Gb memory, 8+8 kB cache, 3.1 million transistotrs, 296 pin SPGA (Staggered Pin Grid Array), built in FPU (Math processor), 2 to 10 times faster than 486, Op. voltage 2.9 V. As the operational voltage is reduced, the power consumption and heat produced is reduced. Uses BiCMOS technology to reduce power consumption (10 to 15 W).

Some Pentium II processors runs at different voltages. So an onboard voltage regulator module (VRM) has been designed to power the CPU. Intel Celeron outperforms Pentium II at the same speed and at a lower cost. Faster Xeon processor uses 2 MB L2 cache.

FPU bug in Pentium : While working with MS Excel,
962306957033/11010046=87402.6282027341, this result is not reached. It caused Intel to replace all of its processors showing the bug.

Pentium !!! runs at 1 GHz, bus speed of 133 MHz, 256 k L2 cache, 75 C op. temp, 1.75 V, 29 W, 28.1 million transistors.

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Glossary of Unix programming

absolute path
The complete pathname to a file starting at the root directory /.

abstraction
Scripts that use abstraction retain the same basic flow by placing the conditional execution statements within functions. When a function is called, it makes a decision as to what commands execute for a given platform.

anchoring expression
Normally any part of a line will be matched by a regular expression. To match expressions that either begin or end a line, you need to anchor the regular expression. The ^ character anchors regular expressions to the beginning of a line, whereas the $ character anchors regular expressions to the end of a line.

argument
Command modifiers that change the behavior of a command. In the shell, they are specified after a command’s name.

array variable
A mechanism available in bash and ksh for grouping scalar variables together. The scalar variables stored in an array are accessed using a single name in conjunction with a number. This number is referred to as an index.

awk
The awk command is a power pattern matching language that allows you to modify input lines by manipulating the fields they contain.