Hardware
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Hardware
Von Neuman Architecture Design model for a
computer Named after John
von Neuman Instructions that
tell the computer what to do are stored in memory
Stored program
Memory
CPU
Input Output
Memory
The working memory of the computer
Where program and data are stored RAM ROM Cache Flash Memory
Volatile and non-volatile memory
Memory Organization
You can think of memory as consisting of a number of boxes
Each box can hold a number Contents
Each box is numbered Address
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
Bit
A bit is the basic unit of information in computing
A bit can be in one of two distinct states. In other words it can be used to represent two distinct things
Because one bit can only represent two distinct values, computers typically work with more than one bit at a time. Much like a single digit can only represent 10 things
and we typically use numbers with more than one digit
Combining Bits
2 states (0 or 1 )
4 states (00, 01, 10 or 11 )
8 states (the 4 from before – twice)
16 states (the 8 from before – twice)
32 states (2 x 2 x 2 x 2 x 2)
64 states (26)
Memory Sizes
Central Processing Unit (CPU) “Brain” of the
computer
Can execute a fixed number of instructions Instructions are
numbered Instructions are very
simple
CPU Architecture
A CPU usually has registers Memory locations in
the CPU Small number of them Usually very fast
One register is called the program counter (PC) The PC stores the
address of the next instruction to execute
PC
R1
R2
Sample Instruction Set
Number
Description
49 Move content of R1 to specified memory location
50 Move content of R2 to specified memory location
65 Move contents of specified memory location to R1
66 Move contents of specified memory location to R2
87 Add contents of R1 to R2 (result stored in R2)
91 Move contents of R1 to R2
92 Move contents of R2 to R1
211 Send contents of R1 to output
219 Input number store in register R1
255 Stop execution
Your First Program
Instruction
219
91
219
87
92
211
255
Input number into R1
Move R1 to R2
Input number into R1
Add R1 to R2
Move R2 to R1
Output number in R1
Halt
Fetch Execute Cycle
The processor runs what is known as the fetch-execute cycle
1. Fetch instruction whose address is in the PC
2. Add one to the PC3. Execute the instruction4. Go back to step 1
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 0
R1: 0
R2: 0
IR: 0
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 0
R1: 0
R2: 0
IR: 219
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 1
R1: 0
R2: 0
IR: 219
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 1
R1: 24
R2: 0
IR: 219
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 1
R1: 24
R2: 0
IR: 91
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 2
R1: 24
R2: 0
IR: 91
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 2
R1: 24
R2: 24
IR: 91
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 2
R1: 24
R2: 24
IR: 219
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 3
R1: 24
R2: 24
IR: 219
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 3
R1: 35
R2: 24
IR: 219
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 3
R1: 35
R2: 24
IR: 87
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 4
R1: 35
R2: 24
IR: 87
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 4
R1: 35
R2: 59
IR: 87
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 4
R1: 35
R2: 59
IR: 92
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 5
R1: 35
R2: 59
IR: 92
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 5
R1: 59
R2: 59
IR: 92
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 5
R1: 59
R2: 59
IR: 211
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 6
R1: 59
R2: 59
IR: 211
59
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 6
R1: 59
R2: 59
IR: 255
Running our Program
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
PC: 7
R1: 59
R2: 59
IR: 255
HALT!!
Programming
What we just did Define a problem Prepare sequence of instructions for the
computer to execute
What do you think? Want to do this for a living?
Did you Realize?
Be honest, did you realize this was a program?
In memory a program looks just like numbers
Number can be manipulated!!
What happens if I add one to memory location 1 and run the program?
Address Contents
0 219
1 91
2 219
3 87
4 92
5 211
6 255
7 543
8 4632
9 212
10 1
Program as Data
Realizing that a program is data was a huge insight
It is possible to write programs that write programs
Ushered in programming languages
Processors Speeds
The processor speed is the speed in which the CPU can complete a certain amount of cycles per second. This is otherwise known as a Hertz. One Hertz means that one cycle can be completed in one second. A megahertz means that one million cycles can be completed in a
second. A gigahertz means that per second, the process can handle one billion
cycles.
The average processor speed today is on the order of 2 gigahertz.
The speed of a processor roughly corresponds to the number of instructions that can be executed in a fixed period of time.
Overclocking
Processors are designed to run at a specific speed, however, they are often designed to handle faster speeds
Overclocking refers to running your processor at a higher speed than it was designed for
System requires more power, generates more heat, and the lifespan of the processor is often shortened
Moore’s Law
Number of transistors on a chip doubles roughly every 2 years
Named after Gordon Moore one of the founders of Intel
Basically means we can expect performance to double every two years
Cores
It is now possible to place multiple CPUs, cores, on a single chip. For example a quad-core processor has 4 CPUs
Using such a chip allows a processor to do more than one thing at a time.
The software running on a multi-core chip must be written to take advantage of the cores.
Motherboard
A motherboard provides the electrical connections by which the other components of the system communicate.
A typical desktop computer has its microprocessor, main memory, and other essential components connected to the motherboard.
Graphics Cards
A video card, video adapter, graphics accelerator card, display adapter, or graphics card is an expansion card which generates output images to a display
Video hardware is often integrated into the motherboard, however all modern motherboards provide expansion ports to which a video card can be attached.
A dedicated graphics card has its own RAM and Processor specifically for processing video images.
Storage
Memory provides temporary storage for information. Most systems require some form of permanent storage.
Magnetic hard drives are probably the most common form of storage
Most systems also usually have 1 or 2 CD/DVD (optical) drives
Hard Disk Drive (HDD)
A hard disk drive is a non-volatile, random access storage device.
It contains rotating platters on which data is magnetically read and written to. Read write heads float on a film of air above the platters.
Introduced by IBM in 1956, hard disk drives have decreased in cost and physical size over the years while dramatically increasing in capacity.
How Data is Stored
Data is stored on the surface of a platter in sectors and tracks.
Tracks are concentric circles
Sectors are pie-shaped wedges on a track
Performance
A typical desktop machine will have a hard disk with a capacity of between 250 and 500 gigabytes.
There are two ways to measure the performance of a hard disk: Data rate - The data rate is the number of bytes per
second that the drive can deliver to the CPU. Rates between 5 and 40 megabytes per second are common.
Seek time - The seek time is the amount of time between when the CPU requests a file and when the first byte of the file is sent to the CPU. Times between 10 and 20 milliseconds are common.
Capacity
Input/Output
Most computers provide a variety of connections for external devices USB, or Universal Serial Bus, is a hardware
bus standard that allows users to plug a peripheral device into a USB port and have it automatically configured and ready to use.
FireWire is Apple's name for the IEEE 1394 High Speed Serial Bus. It was initiated by Apple (in 1986) and developed by the IEEE P1394 Working Group.
Network
Virtually every computer has support for connecting to a network. The connection can either be wired or wireless A wired connection requires access to a
router or switch. A wireless connection requires access to
a wireless access point
Wireless Networking
Wireless networks transmit at frequencies of 2.4 GHz or 5 GHz. The higher frequency allows the signal to carry more data.
Wireless networks use 802.11 networking standards, which come in several flavors: 802.11a transmits at 5 GHz and can move up to 54 megabits
of data per second. 802.11b is the slowest and least expensive standard. It can
handle up to 11 megabits of data per second. 802.11g transmits at 2.4 GHz like 802.11b, but it's a lot
faster -- it can handle up to 54 megabits of data per second. 802.11n is the newest standard that is widely available and
can achieve speeds as high as 140 megabits per second.
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