Ch.5
Von Neumann Bottleneck
the inability of the sequential one-instruction-at-a-time Von Neumann Model to handle todays large scale problems.
Seek time
time needed to position the Read/Write head to the correct position
Read-Only Memory (ROM)
type of Random Access Memory into which information has been prerecorded during manufacturing. It cannot be modified or removed, only fetched.
MIMD Parallel Processing
a computer system has multiple, independent processors each with its own primary memory unit, and every processor is capable of executing its own separate program in its own private memory at its own rate.
Sequential Execution of Instruction
In which one instruction at a time is fetched from memory and passed to the control unit, where it is decoded and executed
Stored Program Concept
In which the instructions to be executed by the computer are represented as binary values and stored in memory
Volatile Memory
Information disappears when the power is turned off
Nonvolatile Memory
Information is saved between shutdown of the machine
Fetch (address), 3 steps
Load the address into the MAR, Decode the address in the MAR, Copy the contents of that memory location into the MDR.
Store (address, value), 4 steps
Load the address into the MAR, Load the Value into the MDR, Decode the address in the MAR, Store the contents of the MDR into that memory location.
Parallel Processing
Many Processing units operating at the same time.
Memory Units contain 2 Registers
Memory Address Register (MAR), Memory Data Register (MDR)
Arithmetic/Locit Unit (ALU)
is the subsystem that performs such mathematical and Logical operations such as addition, subraction, and comparison for equality
Control Unit task 1- Fetch
retrieve from memory the next instructions to be executed
Register
special high-speed storage cell that holds the operands of an arithmetic operation and that, when the operations is complete, holds its results
Machine Language
the instructions that can be decoded and executed by the control unit of a computer. to perform simple tasks
Nondestructive
the origional contents of the memory cell remain unchanged
Cache Hit Rate
the percent of time the cache is utilized over the RAM
Destructive
the previous contents of the cell are lost
Parallel Algorithm
the study of techniques that make efficient use of parallel architectures, is an important branch of research in computer science.
Latency
time for the beginning of the desired sector to rotate under the Read/Write head
Transfer
time for the entire sector to pass under the Read/Write head and have its contents read into or written form memory
Access time
time it takes to find ay sector
ROM
used to hold important system instructions and data in a place where a user cannot accidentally or intentionally overwrite them.
Random Access Memory (RAM)
what the memory units are frequently refereed to as
Source Cell
where it is now
Destination Cell
where it will go
Use power of ____ for time
10
a computer with 16 bit address has 65,536 Bytes of storage and __________ of memory
64kb
ALU will consist of _____-_____registers to hold all the values
16-128
Use power of ____ for storage
2
Von Neumann Architecture is based on 3 principles
4 major subsystems, Stored Program Concept, Sequential Execution of Instruction.
Average Memory Access Time
5-10 nanoseconds
Cashe Memory is usually _______ times faster than RAM but much smaller, on the order of a few ______ rather than ________
5-10, MB, GB
concept of ___________ is used throughout computer science. (transistors to gates, gates to circuits)
Abstraction
Central Processing Unit (CPU)
ALU and Control Unit are often bundled together
Processor (CPU)
ALU and Control unit are joined together to create a single component
Computer Organization
Branch of computer science that studies computer in terms of their major functional units or subsystems
I/O Controller has a memory location called _____
Buffer
_________ Machines Includes a much larger number of very powerful instructions in the instruction set
CISC Machines
Sum of products algorithm
Circuit construction algorithm that allows us to design circuit.
Multiple Instruction Stream/ Multiple Data Stream (MIMD) Parallel Processing is also called
Cluster Computing
It is the task of the _______________ to fetch and execute instructions
Control Unit
Operation of Fetch. Value=Fetch (address)
Copy the contents of an address and return the contents as a result. Nondestructive Fetch, the origional contents of the memory cell remain unchanged
Machine Language Instructions can be grouped into 4 basic classes
Data Transfer, Arithmetic, Compare, Branch
CISC Machines
Designed to directly provide a wide range of powerful features so that the finished programs for these processors are shorter.
Control Unit task 2- Decode
Determine what is to be done
Mass Storage Systems come in 2 forms
Direct Access Storage Device (DASD), Sequential Access Storage Device (SASD)
Register
Does not have a numeric memory address but are access by a special register designator, such as A, X, R
SASD
Does not require that all units of data identifiable via unique addresses
Grid Computing
Enables researchers to easily and transparently access unused computer facilities without regard for their location. like renting out your home or car when its not being used.
Control Unit task 3- Execute
Execute it by using the appropriate command to the ALU, Memory, or I/O controllers
2 basic memory operations
Fetch and Store
Control Unit. (Has 3 Tasks)
Fetch, Decode, Execute.
RAM consists of 3 charatoristics
Memory is dived into cells and each cell has its own unique address. Address consists of unsigned integers from 0-max. the time it takes to fetch or store the contents of a single cell is the same for all cells in memory.
4 Major Subsystems
Memory, Input/Output, Arithmetic/ Logic Units (ALU), and the Control Units.
Mass Storage Systems (Data Centers)
Nonvolatile storage such as disks, flash drives, tapes and servers
Register
Not used for general purpose storage but for specific purposes such as holding operands for an upcoming arithmetic computation
Bus
Path for electrical signals
Control Unit relies on 2 special Registers called _________ and _________ and on a __________ circuit.
Program Counter (PC), Instruction Register(IR), Instruction Decoder Circuit.
__________ Machines designing instruction sets to make them as small and as simple as possible
RISC Machines
what are the 2 approaches to designing instruction sets
Reduced Instruction Set Computers (RISC Machines), Complex Instruction Set Computers (CISC Mashines)
ALU is made up of 3 parts, which together create the Data path
Register, Interconnecitons between components, ALU circuitry
Memory locations in 2 dimensions start with the
Row designation.
Principle of Locality
Says that when the coputer uses something it will probably use it again very soon
Magneti Disk
Sectors, stores information in these units.
Acess time = _________ + _________ + __________
Seek time, Latency, Transfer
Stored Program
Sequence of machine language instructions stored as binary values in memory
Interrupt Signal
Special hardware signal sent to the processor when the I/O operation is done
Condition Codes
Special set of bits inside the processor
Condition codes are special set of bits inside the processor often called _________ or _________
Status Register, Conditin Register
Operation of Store Store (Address, value)
Store the specified value into the memory cell specified. Destructive store, the previous contents of the cell are lost
Von Neumann Architecture
Structure and organization of virtually all modern computational devices
Cache Memory
The first time a computer references a piece of data, it should copy that data from the RAM memory to a special, high speed memory Unit.
Instruction Set
The set of all operations that can be executed by a processor. (every processor is different)
Arithmetic
These operations cause the ALU to perform a computation.
Compare
These operations compare two alues and set an indicator on the basis of the results of the compare
Data Transfer
These operations move information between or within the different components of a computer
RISC Machines
This approach minimize the amount of hardware circuitry needed to build a processor.
Fetch/Store Controller
This unit determines whether we put the contents of a memory cell into the MDR, or put the contents of the MDR into the memory cell
Memory Access Time
Time it takes to carry out a fetch or store operation. (which is the same for all 2^n addresses)
Range of addresses available on a computer is ________
[0.......(2^n-1)]
Random Acess
an access technique the computer memory uses
Input/Output (I/O) Units
are the devices that allow a computer system to communicate and interact with the outside word as well as store information for the long term
Address Fields
are the memory addresses of the values on which this operation will work
Status Register and Condition Register
bits are set aside by the compare operations. 3 1-bit operations. (GT, EQ, LT)
Memory Width (cell size)
bits per cell. Usually denoted as W. Standard cell size is universally a Byte
Register
can be accessed much more quikly than reguar memory cells because there are only a few of them. 5-10 times faster.
MDR
contains the data value being fetched or stored. Size, usually multiles of 8, typically 32 bit and 64 bit This allows us to fetch, in a sing step, either integer or real value respectivly
DASD
every unit of information still has a unique address, but the time needed to access it depends on its physical location and current state of the device
Instruction Register (IR)
holds a copy of the instructions just fetched from memory
MAR
holds the address of the cell to be accessed. must be N bits wide, wehre 2^n is the address space of the computer
Program Counter (PC)
holds the address of the next instruction to be executed.
Operation Code (Op Code)
is a unique unsigned integer value assigned to each machine language operation recognized by the hardware
I/O Controller is
is like a special purpose computer whose responsibility is to handle the details of input/output and to compensate for any speed difference between the I/O devie and other parts of the compmuter
Momory
is the functional unit of a computer that stores and retrieves instructions and data