DIGITAL LOGIC

POWERED BY AL ARIF BIN MOHD JAN (S1G1)

INPUT AND OUTPUT

POWERED BY NUR LIYANA AMIRA BINTI AZHAR (S1G2)

WHAT IS A PROCESSOR?

What is a processor?

·        A processor is the logic circuitry that responds to and processes the basic instructions that drive a computer.

·        The term processor has generally replaced the term central processing unit (CPU). The processor in a personal computer or embedded in small devices is often called a microprocessor.

powered by Nurul Adilla binti Mohd Nordin (S1G1)

CPU :)

Central Processing Unit(CPU)

·         A central processing unit (CPU) is the hardware within a computer that carries out the instructions of a computer program by performing the basic arithmetical, logical, control and input/output operations of the system. The term has been in use in the computer industry at least since the early 1960s.^[1] The form, design, and implementation of CPUs have changed over the course of their history, but their fundamental operation remains much the same.

·         A computer can have more than one CPU; this is called multiprocessing. All modern CPUs are microprocessors, meaning contained on a single chip. Some integrated circuits (ICs) can contain multiple CPUs on a single chip; those ICs are called multi-core processors. An IC containing a CPU can also contain memory, peripheral devices, and other components of a computer system; this is called a system on a chip (SoC).

·         Two typical components of a CPU are the arithmetic logic unit (ALU), which performs arithmetic and logical operations, and the control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.

·         Not all computational systems rely on a central processing unit. An array processor or vector processor has multiple parallel computing elements, with no one unit considered the "center". In the distributed computing model, problems are solved by a distributed interconnected set of processors.

powered by Nurul Adilla binti Mohd Nordin (S1G1)

TYPES OF PROCESSORS :)

Processor

v Different types of computer processor

Traditionally computer processor design and innovation has advanced at an exceedingly fast rate. As a corollary, the market for computer processors is vast and often times confusing to a first time explorer. However, learning the key feature sets and functions that set each processor apart from one another is not very difficult at all.

Brands

Since the inception of mainstream computing into the homes of society, but there has been consumer and commercial level computer processor manufacturers. The Intel Corporation is undoubtedly the first name when any consumer thinks of the word processor is mentioned. Intel has been producing the most top-line computer processors for several decades now. AMD or Advanced Micro Devices is Intel's only true competitor in the computer processor market producing computer processors, which rival the speed and power of Intel's.

Architecture

When considering the architecture of a computer processor, there are really only a few key factors to consider. Whether the processor has a 32-bit or 64-bit core determines whether or not the processor can run your software correctly. The amount of on die processor cache memory is also of importance, as this integrated memory space is where processor instructions are held before execution. Finally, is the system a single, dual or quad core processor? While multicore processors do have their advantages there is still a lack of software able to utilize multicore processors.

Clock Speed

The clock speed of a computer processor determines the rate at which a processor executes instructions on data. Today this rate of execution is expressed in billions of instructions per second. Though having a computer processor with a high clock speed is advantageous, it alone is not the only factor that dictates overall system performance. Higher clock speeds increase all system tasks, such as web browsing, movie encoding, and system utilities like anti-virus software.

Maintenance

Computer processors must be maintained according to their manufacturer's specifications in order to perform at their full potential. All too often consumers will pick an expensive cutting edge processor while neglecting support hardware for their processor. Different processors require different power supplies, proper heat sink/ fan combos, and adequate memory in order to function correctly. Above all, different processors require different cooling solutions. Each processor has its own TDP (Thermal Design Power) which is an indication of heat output which must be dissipated.

Current Model

The most recent offerings from Intel and AMD are the Core i7 quad core and Phenom II quad core processors respectively. The Core i7 supersedes the Core 2 series of dual and quad core Intel processors and the Phenom II supersedes the Phenom I dual and quad core model AMD processors. Outside of extreme gaming or high-end 3D graphics applications, even the Phenom II and Core 2 older model processors are more than adequate for the home user and come at a much lower price point in most cases.

(Source from :blogger.2014. http://computer-help-tips.blogspot.com/2011/04/different-types-of-computer-processors.html)

powered by Nurul Adilla binti Mohd Nordin(S1G1)

ARITHMETIC FOR COMPUTER(NUMBER SYSTEM AND OPERATION) BY ARMILA AZIRA BT MOHD SHARIFF

When we type some letters or words, the computer translates them in numbers as computers can understand only numbers. A computer can understand positional number system where there are only a few symbols called digits and these symbols represent different values depending on the position they occupy in the number.

A value of each digit in a number can be determined using

• The digit
• The position of the digit in the number
• The base of the number system (where base is defined as the total number of digits available in the number system).

Decimal Number System

The number system that we use in our day-to-day life is the decimal number system. Decimal number system has base 10 as it uses 10 digits from 0 to 9. In decimal number system, the successive positions to the left of the decimal point represent units, tens, hundreds, thousands and so on.

Each position represents a specific power of the base (10). For example, the decimal number 1234 consists of the digit 4 in the units position, 3 in the tens position, 2 in the hundreds position, and 1 in the thousands position, and its value can be written as

(1x1000)+ (2x100)+ (3x10)+ (4xl)
(1x103)+ (2x102)+ (3x101)+ (4xl00)
1000 + 200 + 30 + 4
1234

As a computer programmer or an IT professional, you should understand the following number systems which are frequently used in computers.

S.N.	Number System and Description
1	Binary Number System Base 2. Digits used : 0, 1
2	Octal Number System Base 8. Digits used : 0 to 7
3	Hexa Decimal Number System Base 16. Digits used : 0 to 9, Letters used : A- F

Binary Number System

Characteristics of binary number system are as follows:

• Uses two digits, 0 and 1.
• Also called base 2 number system
• Each position in a binary number represents a 0 power of the base (2). Example 2⁰
• Last position in a binary number represents a x power of the base (2). Example 2^xwhere x represents the last position - 1.

Example

Binary Number : 10101₂

Calculating Decimal Equivalent:

Step	Binary Number	Decimal Number
Step 1	101012	((1 x 24) + (0 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10
Step 2	101012	(16 + 0 + 4 + 0 + 1)10
Step 3	101012	2110

Note : 10101₂ is normally written as 10101.

Octal Number System

Characteristics of octal number system are as follows:

• Uses eight digits, 0,1,2,3,4,5,6,7.
• Also called base 8 number system
• Each position in an octal number represents a 0 power of the base (8). Example 8⁰
• Last position in an octal number represents a x power of the base (8). Example 8^xwhere x represents the last position - 1.

Example

Octal Number : 12570₈

Calculating Decimal Equivalent:

Step	Octal Number	Decimal Number
Step 1	125708	((1 x 84) + (2 x 83) + (5 x 82) + (7 x 81) + (0 x 80))10
Step 2	125708	(4096 + 1024 + 320 + 56 + 0)10
Step 3	125708	549610

Note : 12570₈ is normally written as 12570.

Hexadecimal Number System

Characteristics of hexadecimal number system are as follows:

• Uses 10 digits and 6 letters, 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F.
• Letters represents numbers starting from 10. A = 10. B = 11, C = 12, D = 13, E = 14, F = 15.
• Also called base 16 number system
• Each position in a hexadecimal number represents a 0 power of the base (16). Example 16⁰
• Last position in a hexadecimal number represents a x power of the base (16). Example 16^x where x represents the last position - 1.

Example

Hexadecimal Number : 19FDE₁₆

Calculating Decimal Equivalent:

Step	Binary Number	Decimal Number
Step 1	19FDE16	((1 x 164) + (9 x 163) + (F x 162) + (D x 161) + (E x 160))10
Step 2	19FDE16	((1 x 164) + (9 x 163) + (15 x 162) + (13 x 161) + (14 x 160))10
Step 3	19FDE16	(65536+ 36864 + 3840 + 208 + 14)10
Step 4	19FDE16	10646210

Note : 19FDE₁₆ is normally written as 19FDE.

MEMORY ORGANIZATION BY NUR SYAZWANI BINTI ZAINULDDIN

MEMORY

*Memory unit is an essential component in digital computers since it is needed for storing programs and data. Two or three levels of memory such as Main memory Secondary memory and Cache memory are provided in a digital computer. The main memory is a fast memory.

*Main memory stores the programs along with data, which are to be executed. It also stores necessary programs of system software. The cache memory is placed in between the CPU and the main memory. Secondary memory is permanent storage used to store programs and data that are used infrequently.

1)RAM

* It consist of internal latches that store the binary information. The stored information remains    valid as long as power is applied to the unit

* is generally volatile,

* does not retain the data stored in it when the system 's power is turned off.

* Any data that needs to be stored while the system is off must be written to a permanent storage device, such as a flash memory or

hard disk.

There are many kinds of RAM and new ones are invented all the time. One aim is to make RAM

access as fast as possible in order to keep up with the increasing speed of CPUs.

SRAM, DRAM, SDRAM, DDR SDRAM

SRAM (Static RAM)

* is the fastest form of RAM but also the most expensive. Due to its cost it is not used as main memory but rather for cache memory. Each bit requires a 6-transistor circuit.

DRAM (Dynamic RAM)

*is not as fast as SRAM but is cheaper and is used for main memory. Each bit uses a single capacitor and single transistor circuit. Since capacitors lose their charge, DRAM needs to be refreshed every few milliseconds. The memory system does this transparently. There are many implementations of DRAM, two well-known ones are SDRAM and DDR SDRAM.

SDRAM (Synchronous DRAM)

*is a form of DRAM that is synchronised with the clock of the CPU‟s system bus, sometimes called the front-side bus (FSB). As an example, if the system bus operates at 167Mhz over an 8-byte (64-bit) data bus , then an SDRAM module could transfer 167 x 8 ~ 1.3GB/sec.

DDR SDRAM (Double-Data Rate SDRAM)

*is an optimisation of SDRAM that allows data to be transferred on both the rising edge and falling edge of a clock signal, effectively doubling the amount of data that can be transferred in a period of time. For example a PC-3200 DDR-SDRAM module operating at 200Mhz can transfer 200 x 8 x 2 ~ 3.2GB/sec over an 8-byte (64-bit) data bus.DDR3 continues the trend, doubling the minimum read or write unit to 8 consecutive words.

2)ROM

It is non-volatile memory, which retains the data even when power is removed from this memory. Programs and data that can not be altered are stored in ROM.

ROM, PROM, EPROM, EEPROM, Flash

ROM (Read Only Memory)

*is a form of semi-conductor that can be written to once, typically in bulk at a factory. ROM was used to store the “boot” or start-up program (so called firmware) that a computer executes when powered on, although it has now fallen out-of-favour to more flexible memories that support occasional writes. ROM is still used in systems with fixed functionalities,

e.g. controllers in cars, household appliances etc.

PROM (Programmable ROM)

*is like ROM but allows end-users to write their own programs and data. It requires special PROM writing equipment. Note: users can only write-once to PROM.

EPROM (Erasable PROM)

*With EPROM we can erase (using strong ultra-violet light) the contents of the chip and rewrite it with new contents, typically several thousand times. It is commonly used to store the “boot” program of a computer, known as the firmware. PCs call this firmware, the BIOS (Basic I/O System). Other systems use Open Firmware. Intel-based Macs use EFI (Extensible Firmware Interface).

EEPROM (Electrically Erasable PROM)

*As the name implies the contents of EEPROMs are erased electrically. EEPROMSs are also limited to the number of erase-writes that can be performed (e.g, 100,000) but support updates (erase-writes) to individual bytes whereas EPROM updates the whole memory and only supports around 10,000 erase-write cycles.

FLASH memory

*is a cheaper form of EEPROM where updates (erase-writes) can only be performed on blocks of memory, not on individual bytes. Flash memories are found in USB sticks, flash cards and typically range in size from 1GB to 32GB. The number of erase/write cycles to a block is typically several hundred thousand before the block can no longer be written.

Computer memories are divided into Cache memory, main memory and secondary memory. Where Cache is the fastest and closest to processor. Cache memory is also the smallest memory. Secondary memory is the slowest, furthest from processor and largest in size.

CACHE MEMORY

      Cache memory, also called CPU memory, is random access memory (RAM) that a computer microprocessor can access more quickly than it can access regular RAM. 

As the microprocessor processesdata, it looks first in the cachememory and if it finds the data there (from a previous reading of data), it does not have to do the more time-consuming reading of data from larger memory. 

Cache memory is fast and it is expensive. It is categorized in levels that describe its closeness and accessibility to the microprocessor. Level 1 (L1) cache, which is extremely fast but relatively small, is located close to the processor. Level 2 (L2) cache is located half-way between the process and the system bus; it is fairly fast and medium-sized. Level 3 (L3) cache is relatively large and close to RAM.

Memory cache can work under three different configurations: direct mapping, fully associative and set associative. With direct mapping each block is mapped to exactly one cache location. With fully associative mapping, each block is mapped to any cache location. With set associative, each block is mapped to a subset of cache locations.  

EXTERNAL MEMORY

 1. Magnetic disk

 2. Optical

 3. Magnetic tape

magnetic disk

optical disk

magnetic tape

RAID

RAID (redundant array of independent disks; originally redundant array of inexpensive disks) is a way of storing the same data in different places (thus, redundantly) on multiple hard disks. By placing data on multiple disks, i/o(input/output) operations can overlap in a balanced way, improving performance. Since multiple disks increases the mean time between failures , storing data redundantly also increases fault tolerance.

RAID 1

RAID 1 consists of mirroring, without parity or striping. Data is written identically to two (or more) drives, thereby producing a "mirrored set". Thus, any read request can be serviced by any drive in the set. If a request is broadcast to every drive in the set, it can be serviced by the drive that accesses the data first (depending on its seek time androtational latency), improving performance. Sustained read throughput, if the controller or software is optimized for it, approaches the sum of throughputs of every drive in the set, just as for RAID 0.

RAID 2 

RAID 2 consists of bit-level striping with dedicated Hamming-code parity. All disk spindle rotation is synchronized and data is striped such that each sequential bit is on a different drive. Hamming-code parity is calculated across corresponding bits and stored on at least one parity drive. This level is of historical significance only.

RAID 3

RAID 3 consists of byte-level striping with dedicated parity. All disk spindle rotation is synchronized and data is striped such that each sequential byte is on a different drive. Parity is calculated across corresponding bytes and stored on a dedicated parity drive.Although implementations exist, RAID 3 is not commonly used in practice.

RAID 4

RAID 4 consists of block-level striping with dedicated parity. This level was previously used by NetApp, but has now been largely replaced by a proprietary implementation of RAID 4 with two parity disks, called RAID-DP.

RAID 5

RAID 5 consists of block-level striping with distributed parity. Unlike in RAID 4, parity information is distributed among the drives. It requires that all drives but one be present to operate. Upon failure of a single drive, subsequent reads can be calculated from the distributed parity such that no data is lost. RAID 5 requires at least three disks.RAID 5 is seriously affected by the general trends regarding array rebuild time and chance of failure during rebuild.

RAID 6

RAID 6 consists of block-level striping with double distributed parity. Double parity provides fault tolerance up to two failed drives. This makes larger RAID groups more practical, especially for high-availability systems, as large-capacity drives take longer to restore. As with RAID 5, a single drive failure results in reduced performance of the entire array until the failed drive has been replaced. With a RAID 6 array, using drives from multiple sources and manufacturers, it is possible to mitigate most of the problems associated with RAID 5. The larger the drive capacities and the larger the array size, the more important it becomes to choose RAID 6 instead of RAID 5.

Diagram for memory hierarchy

POWERED BY NUR SYAZWANI BINTI ZAINULDDIN  1-BITD(S1G1)