How The Computer Works: The CPU and Memory - The Diigo Meta page

• 08 Sep 16
  

  michaelgriffin7

  INTROCHAP6

• 21 Apr 16
  

  asherv
  • The arithmetic/logic unit (ALU) contains the electronic circuitry that executes  all arithmetic and logical operations.
  • The arithmetic/logic unit can perform four kinds of arithmetic operations, or mathematical calculations: addition, subtraction, multiplication, and division. As its name implies, the arithmetic/logic unit also performs logical operations. A logical operation is usually a comparison. The unit can compare numbers, letters, or special characters. The computer can then take action based on the result of the comparison. This is a very important capability. It is by comparing that
• 

  chrischill1
  • Registers: Temporary Storage Areas
  • • An accumulator, which collects the result of computations. 
    • An address register, which keeps track of where a given instruction or piece of data is stored in memory. Each storage location in memory is identified by an address, just as each house on a street has an address.
  • he released to an output unit.

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  brandonlpagano
  • he computer does its primary work in a part of the machine we cannot see, a control center that converts data input to information output. This control center, called the central processing unit (CPU),

  • Figure 1: The Central Processing Unit

     T
  • The control unit of the CPU contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • The arithmetic/logic unit (ALU) contains the electronic circuitry that executes  all arithmetic and logical operations.
  • A computer can simultaneously test for more than one condition.
  • Memory is also known as primary storage, primary memory, main storage, internal storage, main memory, and RAM (Random Access Memory); all these terms  are used interchangeably by people in computer circles.
  • The chief characteristic of memory is that it allows very fast access to instructions and data, no matter where the items are within it. We will discuss the physical components of memory-memory chips-later in this chapter. 
  • Now for a more technical example. let us look at how a payroll program uses all three types of storage. Suppose the program calculates the salary of an employee. The data representing the hours worked and the data for the rate of pay are ready in their respective registers.
  • Storage Speed  Capacity  Relative Cost ($)  Permanent? Registers Fastest  Lowest Highest  No RAM Very Fast  Low/Moderate High  No Floppy Disk Very Slow  Low Low  Yes Hard Disk Moderate  Very High Very Low  Yes

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• 
  • The CPU interacts closely with primary storage, or main memory, referring to it for both instructions and data. For this reason this part of the reading will discuss memory in the context of the central processing unit. Technically, however, memory is not part of the CPU.
  • The control unit of the CPU contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions. Like an orchestra leader, the control unit does not execute program instructions; rather, it directs other parts of the system to do so.
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  ploza23
  • central processing unit (CPU)
  • arithmetic/logic unit.
  • control unit
  • primary storage, or main memory, referring to it for both instructions and data
  • Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium
  • direct the entire computer system to carry out, or execute, stored program instructions
  • arithmetic/logic unit (ALU) contains the electronic circuitry that executes  all arithmetic and logical operations.
  • addition, subtraction, multiplication, and division
  • comparison
  • ompares two values to determine if they are equal
  • Equal-to condition.
  • compares values to determine if one is less than another
  • Less-than condition.
  • Greater-than condition.
  • determines if one value is greater than another
  • Registers are temporary storage areas for instructions or data.
  • offer the advantage of speed
  • An accumulator
  • An address register
  • A storage register
  • A general-purpose register
  • primary storage, primary memory, main storage, internal storage, main memory, and RAM (Random Access Memory)
  • holds data and instructions for processing
  • store items while the computer is turned on; data is destroyed when the machine is turned off.
  • The refrigerator is the equivalent of secondary (disk) storage. It can store high volumes of veggies for long periods of time. The counter top is the equivalent of the computer's motherboard
  • - everything is done on the counter (inside the computer). The cutting board is the ALU - the work gets  done there. The recipe is the control unit - it tells you what to do on the cutting board (ALU). Space on the counter top is the equivalent of RAM memory - all veggies must be brought from the fridge and placed on the counter top for fast access. Note that the counter top (RAM) is faster to access than the fridge (disk), but can not hold as much, and can not hold it for long periods of time. The corners of the cutting board where we temporarily store partially chopped veggies are equivalent to the registers. The corners of the cutting board are very fast to access for chopping, but can not hold much. The salad bowl is like a temporary register, it is for storing the salad waiting to take back to the fridge (putting data back on a disk) or for taking to the dinner table (outputting the data to an output device).
  • storage hierarchy
  •           

    Storage	Speed	Capacity	Relative Cost ($)	Permanent?
    Registers	Fastest	Lowest	Highest	No
    RAM	Very Fast	Low/Moderate	High	No
    Floppy Disk	Very Slow	Low	Low	Yes
    Hard Disk	Moderate	Very High	Very Low	Yes
  • program instructions and data must be placed into memory from an input device or a secondary storage device
  • • The control unit fetches (gets) the instruction from memory. 
    • The control unit decodes the instruction (decides what it means) and directs that the necessary data be moved from memory to the arithmetic/logic  unit. These first two steps together are called instruction time, or I-time. 
    • The arithmetic/logic unit executes the arithmetic or logical instruction. That is, the ALU is given control and performs the actual operation on the data. 
    • Thc arithmetic/logic unit stores the result of this operation in memory  or in a register. Steps 3 and 4 together are called execution time, or E-time.

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  katieyi53
  • central processing unit (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions.
  • Primary storage and secondary storage
  • primary storage, or main memory, referring to it for both instructions and data.
  • Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium.
  • electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • electronic circuitry that executes  all arithmetic and logical operations. 
    
  • Equal-to condition
  • Less-than condition.
  • Greater-than condition.
  • Registers: Temporary Storage Areas
  • An accumulator, which collects the result of computations.
  • An address register, which keeps track of where a given instruction or piece of data is stored in memory.
  • A storage register, which temporarily holds data taken from or about to be sent to memory.
  • Memory and Storage
     Memory is also known as primary storage, primary memory, main storage, internal storage, main memory, and RAM (Random Access Memory)
  • • The control unit fetches (gets) the instruction from memory. 
    • The control unit decodes the instruction (decides what it means) and directs that the necessary data be moved from memory to the arithmetic/logic  unit. These first two steps together are called instruction time, or I-time. 
    • The arithmetic/logic unit executes the arithmetic or logical instruction. That is, the ALU is given control and performs the actual operation on the data. 
    • Thc arithmetic/logic unit stores the result of this operation in memory  or in a register. Steps 3 and 4 together are called execution time, or E-time.
  • Each central processing unit has an internal clock that produces pulses at a fixed rate to synchronize all computer operations

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  sherwin_jay
  • This control center, called the central processing unit (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions
  • Recall that a computer's memory holds data only temporarily, at the time the computer is executing a program
  • The control unit of the CPU contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions. Like an orchestra leader, the control unit does not execute program instructions; rather, it directs other parts of the system to do so.

  1 more annotation...

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  freddief83
  • This control center, called the central processing unit (CPU)
  • highly complex,  extensive set of electronic circuitry that executes stored program instructions
  • The control unit and the arithmetic/logic unit
  • The CPU interacts closely with primary storage, or main memory
  • memory is not part of the CPU
  • Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium
  • The diskettes and CD-ROM disks that you have seen with personal computers are secondary storage devices, as are hard disks.
  • The control unit of the CPU contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • directs
  • must communicate with both the arithmetic/logic unit and memory
  • The arithmetic/logic unit (ALU) contains the electronic circuitry that executes  all arithmetic and logical operations.
  • four kinds of arithmetic operations, or mathematical calculations: addition, subtraction, multiplication, and division
  • usually a comparison
  • performs logical operations
  • Equal-to condition
  • compares two values to determine if they are equal
  • compares values to determine if one is less than another
  • Less-than condition
  • Greater-than condition
  • if one value is greater than another
  • A computer can simultaneously test for more than one condition
  • The symbols that let you define the type of comparison you want the  computer to perform are called relational operators
  • equal sign(=), the less-than symbol(<), and the  greater-than symbol(>). 
    
  • offer the advantage of speed
  • Registers are temporary storage areas for instructions or data.
  • An accumulator, which collects the result of computations
  • An address register, which keeps track of where a given instruction or piece of data is stored in memory
  • A storage register, which temporarily holds data taken from or about to be sent to memory.
  • Memory is also known as primary storage, primary memory, main storage, internal storage, main memory, and RAM (Random Access Memory)
  • • Most types of memory only store items while the computer is turned on; data is destroyed when the machine is turned off. 
    • If more than one program is running at once (often the case on large computers and sometimes on small computers), a single program can not lay exclusive claim to memory. 
    • There may not be room in memory to hold the processed data.
  • execute only one instruction at a time, though they execute it very quickly
  • • The control unit fetches (gets) the instruction from memory. 
    • The control unit decodes the instruction (decides what it means) and directs that the necessary data be moved from memory to the arithmetic/logic  unit
  • The arithmetic/logic unit executes the arithmetic or logical instruction
  • Thc arithmetic/logic unit stores the result of this operation in memory  or in a register
  • combination of I-time and E-time is called the machine cycle
  • Each central processing unit has an internal clock that produces pulses at a fixed rate to synchronize all computer operations
  • each different type of CPU has an instruction set it understands
  • he name is called a symbolic address. In this example, the symbolic address names are Rate, Hours, and Salary.

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  moose56

  computer CPU technology howstuffworks

  • CPU, Buses, Controllers, and Main Memory.
  • control center,
  • central processing unit (CPU)
  • All computers, large and small, must have a central processing unit
  • Computers use two types of storage: Primary storage and secondary storage.
  • Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium.
  • secondary storage devices, as are hard disks
  • The control unit of the CPU contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • The arithmetic/logic unit (ALU) contains the electronic circuitry that executes  all arithmetic and logical operations.
  • Logical operations can test for three conditions: 
     
     
    • Equal-to condition. In a test for this condition, the arithmetic/logic  unit compares two values to determine if they are equal. For example: If the number of tickets sold equals the number of seats in the auditorium, then the concert is declared sold out. 
       
    • Less-than condition. To test for this condition, the computer compares values to determine if one is less than another. For example: If the number of speeding tickets on a driver's record is less  than three, then insurance rates are $425; otherwise, the rates are $500. 
       
    • Greater-than condition. In this type of comparison, the computer  determines if one value is greater than another. For example: If the hours a person worked this week are greater than 40, then multiply every extra hour by 1.5 times the usual hourly wage to compute overtime pay.
  • Registers: Temporary Storage Areas
  • Computers usually assign special roles to certain registers, including these registers:
  • An accumulator,
  • An address register
  • A storage register
  • A general-purpose register

  • To see how registers, memory, and second storage all work together, let us use the analogy of making a salad. In our kitchen we have: 

     
    • a refrigerator where we store our vegetables for the salad; 
    • a counter where we place all of our veggies before putting them  on the cutting board for chopping; 
    • a cutting board on the counter where we chop the vegetables; 
    • a recipe that details what veggies to chop; 
    • the corners of the cutting board are kept free for partially chopped piles of veggies that we intend to chop more or to mix with other partially chopped veggies. 
    • a bowl on the counter where we mix and store the salad; 
    • space in the refrigerator to put the mixed salad after it is made.
  • most computers today can execute only one instruction at a time, though they execute it very quickly. Many personal computers can execute instructions in less than one-millionth of a second, whereas those speed demons known as supercomputers can execute instructions in less than one-billionth of a second.
  • As Figure 2 shows, once the necessary data and instruction are in memory, the central  processing unit performs the following four steps for each instruction:
  • • The control unit fetches (gets) the instruction from memory. 
    • The control unit decodes the instruction (decides what it means) and directs that the necessary data be moved from memory to the arithmetic/logic  unit. These first two steps together are called instruction time, or I-time. 
    • The arithmetic/logic unit executes the arithmetic or logical instruction. That is, the ALU is given control and performs the actual operation on the data. 
    • Thc arithmetic/logic unit stores the result of this operation in memory  or in a register. Steps 3 and 4 together are called execution time, or E-time.
  • Each central processing unit has an internal clock that produces pulses at a fixed rate to synchronize all computer operations.
  • Each type of central processing unit is designed to understand a specific group of instructions called the instruction set. Just as there are many different languages that people understand, so each different type of CPU has an instruction set it understands. Therefore, one CPU-such as the one for a Compaq personal computer-cannot understand the instruction set from another CPU-say, for a Macintosh.
  • The location in memory for each instruction and each piece of data is identified by an address.
  • a memory location can hold only a fixed amount of data; an address can hold only a fixed number of bytes - often two bytes in a modern computer.
  • Figure 4 shows how a program manipulates data in memory
  • o compute the employee's salary, then, instructions tell the computer to multiply the data in location 3 by the data in location 6 and move the result to location 8.

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  abdallahothman
  • The computer does its primary work in a part of the machine we cannot see, a control center that converts data input to information output. This control center, called the central processing unit (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions. All computers, large and small, must have a central processing unit. As Figure 1 shows, the central processing unit consists of two parts: The control unit and the arithmetic/logic unit. Each part has a specific function. 
  • Before we discuss the control unit and the arithmetic/logic unit in detail, we need to consider data storage and its relationship to the central processing unit. Computers use two types of storage: Primary storage and secondary storage. The CPU interacts closely with primary storage, or main memory, referring to it for both instructions and data. For this reason this part of the reading will discuss memory in the context of the central processing unit. Technically, however, memory is not part of the CPU. 
     
     Recall that a computer's memory holds data only temporarily, at the time the computer is executing a program. Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium. The diskettes and CD-ROM disks that you have seen with personal computers are secondary storage devices, as are hard disks. Since the physical attributes of  secondary storage devices determine the way data is organized on them, we will  discuss secondary storage and data organization together in another part of our on-line readings. 
     
     Now let us consider the components of the central processing unit. 
    
  • The Control Unit 
     The control unit of the CPU contain
  • The Arithmetic/Logic Unit
  • Logical operations can test for three conditions: 
     
     
    • Equal-to condition. In a test for this condition, the arithmetic/logic  unit compares two values to determine if they are equal. For example: If the number of tickets sold equals the number of seats in the auditorium, then the concert is declared sold out. 
       
    • Less-than condition. To test for this condition, the computer compares values to determine if one is less than another. For example: If the number of speeding tickets on a driver's record is less  than three, then insurance rates are $425; otherwise, the rates are $500. 
       
    • Greater-than condition. In this type of comparison, the computer  determines if one value is greater than another. For example: If the hours a person worked this week are greater than 40, then multiply every extra hour by 1.5 times the usual hourly wage to compute overtime pay.
  • special roles to certain registers,
  • • • An accumulator, which collects the result of computations. 
      • An address register, which keeps track of where a given instruction or piece of data is stored in memory. Each storage location in memory is identified by an address, just as each house on a street has an address. 
      • A storage register, which temporarily holds data taken from or about to be sent to memory. 
      • A general-purpose register, which is used  for several functions.  
       

        

    • Memory and Storage
  • • Most types of memory only store items while the computer is turned on; data is destroyed when the machine is turned off. 
    • If more than one program is running at once (often the case on large computers and sometimes on small computers), a single program can not lay exclusive claim to memory. 
    • There may not be room in memory to hold the processed data. 
  • • a refrigerator where we store our vegetables for the salad; 
    • a counter where we place all of our veggies before putting them  on the cutting board for chopping; 
    • a cutting board on the counter where we chop the vegetables; 
    • a recipe that details what veggies to chop; 
    • the corners of the cutting board are kept free for partially chopped piles of veggies that we intend to chop more or to mix with other partially chopped veggies. 
    • a bowl on the counter where we mix and store the salad; 
    • space in the refrigerator to put the mixed salad after it is made.

  • The refrigerator is the equivalent of secondary (disk) storage. It can store high volumes of veggies for long periods of time. The counter top is the equivalent of the computer's motherboard - everything is done on the counter (inside the computer). The cutting board is the ALU - the work gets  done there. The recipe is the control unit - it tells you what to do on the cutting board (ALU). Space on the counter top is the equivalent of RAM memory - all veggies must be brought from the fridge and placed on the counter top for fast access. Note that the counter top (RAM) is faster to access than the fridge (disk), but can not hold as much, and can not hold it for long periods of time. The corners of the cutting board where we temporarily store partially chopped veggies are equivalent to the registers. The corners of the cutting board are very fast to access for chopping, but can not hold much. The salad bowl is like a temporary register, it is for storing the salad waiting to take back to the fridge (putting data back on a disk) or for taking to the dinner table (outputting the data to an output device).  
  • 1. The control unit fetches (gets) the instruction from memory. 
    2. The control unit decodes the instruction (decides what it means) and directs that the necessary data be moved from memory to the arithmetic/logic  unit. These first two steps together are called instruction time, or I-time. 
    3. The arithmetic/logic unit executes the arithmetic or logical instruction. That is, the ALU is given control and performs the actual operation on the data. 
    4. Thc arithmetic/logic unit stores the result of this operation in memory  or in a register. Steps 3 and 4 together are called execution time, or E-time. 
     
     The control unit eventually directs memory to release the result to an output device or a secondary storage device. The combination of I-time and E-time is called the machine cycle. Figure 3 shows an instruction going through the machine cycle. 
    

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  arianabhatia
  • (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions
  • control unit and the arithmetic/logic unit
  • The CPU interacts closely with primary storage
  • memory is not part of the CPU
  • The control unit of the CPU contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • that executes  all arithmetic and logical operations.
  • or mathematical calculations: addition, subtraction, multiplication, and division
  • comparison
  • Equal-to condition.
  • Less-than condition.
  • Greater-than condition.
  • temporary storage areas for instructions or data
  • An accumulator, which collects the result of computations.
  • An address register, which keeps track of where a given instruction or piece of data is stored in memory
  • A storage register, which temporarily holds data taken from or about to be sent to memory.
  • A general-purpose register, which is used  for several functions.
  • RAM (Random Access Memory)
  • chief characteristic of memory is that it allows very fast access to instructions and data,

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  sgbarrena
  • The Central Processing Unit (CPU)
  • This control center, called the central processing unit (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions.
  • Computers use two types of storage: Primary storage and secondary storage.
  • CPU interacts closely with primary storage
  • referring to it for both instructions and data.
  • Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium.
  • Now let us consider the components of the central processing unit. 
    
  • The Control Unit
  • contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • The Arithmetic/Logic Unit
  • contains the electronic circuitry that executes  all arithmetic and logical operations. 
    
  • The arithmetic/logic unit can perform four kinds of arithmetic operations
  • addition, subtraction, multiplication, and division
  • The unit can compare numbers, letters, or special characters.
  • Logical operations can test for three conditions:
  • Equal-to condition.
  • Less-than condition.
  • Greater-than condition.
  • Registers: Temporary Storage Areas
  • Registers are temporary storage areas for instructions or data.

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  mattgrieco10
  • a control center that converts data input to information output
  • a highly complex,  extensive set of electronic circuitry that executes stored program instructions
  • must have a central processing unit.
  • Primary storage and secondary storage.
  • econdary storage holds permanent or semi-permanent data on some external magnetic or optical medium

  •   

    Figure 1: The Central Processing Unit

     The computer does its primary work in a part of the machine we ca
  • Equal-to condition.
  • ess-than condition
  • reater-than condition
  • ix logical relationships: equal to, less than, greater than, less than or equal to, greater than or equal to, and not equal.
  • The most common relational operators are the equal sign(=), the less-than symbol(<), and the  greater-than symbol(>).
  • The refrigerator is the equivalent of secondary (disk) storage. It can store high volumes of veggies for long periods of time. The counter top is the equivalent of the computer's motherboard - everything is done on the counter (inside the computer). The cutting board is the ALU - the work gets  done there. The recipe is the control unit - it tells you what to do on the cutting board (ALU). Space on the counter top is the equivalent of RAM memory - all veggies must be brought from the fridge and placed on the counter top for fast access. Note that the counter top (RAM) is faster to access than the fridge (disk), but can not hold as much, and can not hold it for long periods of time. The corners of the cutting board where we temporarily store partially chopped veggies are equivalent to the registers. The corners of the cutting board are very fast to access for chopping, but can not hold much. The salad bowl is like a temporary register, it is for storing the salad waiting to take back to the fridge (putting data back on a disk) or for taking to the dinner table (outputting the data to an output device).
  • Storage Speed  Capacity  Relative Cost ($)  Permanent? Registers Fastest  Lowest Highest  No RAM Very Fast  Low/Moderate High  No Floppy Disk Very Slow  Low Low  Yes Hard Disk Moderate  Very High Very Low  Yes

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  kevinbarruffe

  computer CPU

  • a control center that converts data input to information output.
  • Like an orchestra leader, the control unit does not execute program instructions; rather, it directs other parts of the system to do so.
  • mathematical calculations: addition, subtraction, multiplication, and division.
  • Memory is the part of the computer that holds data and instructions for processing.
  • o see how registers, memory, and second storage
  • In our kitchen
  • making a salad.
  • The counter top is the equivalent of the computer's motherboard
  • The refrigerator is the equivalent of secondary (disk) storage.
  • The cutting board is the ALU
  • The recipe is the control unit -
  • Note that the counter top (RAM) is faster to access than the fridge (disk)
  • Space on the counter top

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• 
  • CPU, Buses, Controllers, and Main Memory.
  • a control center that converts data input to information output
  • central processing unit (CPU)
  • large and small, must have a central processing unit.
  • two parts: The control unit and the arithmetic/logic unit.
  • The CPU interacts closely with primary storage, or main memory,
  • Primary storage and secondary storage
  • memory is not part of the CPU.
  • Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium.
  • computer's memory holds data only temporarily
  • The Control Unit
  • carry out, or execute, stored program instructions.
  • it directs other parts of the system to do so
  • The Arithmetic/Logic Unit
  • electronic circuitry that executes  all arithmetic and logical operations.
  • four kinds of arithmetic operations, or mathematical calculations: addition, subtraction, multiplication, and division.
  • compare numbers, letters, or special characters
  • Logical operations can test for three conditions:
  • less than
  • A computer can simultaneously test for more than one condition.
  • greater than
  • equal to
  • less than or equal to
  • greater than or equal to
  • six logical relationships
  • not equal
  • Registers: Temporary Storage Areas
  • temporary storage areas for instructions or data.
  • o accept, hold, and transfer instructions or data and perform arithmetic or logical comparisons at high speed.
  • Memory and Storage
  • primary storage, primary memory, main storage, internal storage, main memory, and RAM (Random Access Memory);
  • holds data and instructions for processing.
  • stores program instructions or data for only as long as the program they pertain to is in operation.
  • data is destroyed when the machine is turned off.
  • while the computer is turned on
  • The following table summarizes the characteristics of the various kinds of data storage in the storage hierarchy.
  • How the CPU Executes Program Instructions
  • can execute only one instruction at a time, though they execute it very quickly
  • program instructions and data must be placed into memory from an input device or a secondary storage device
  • four steps
  • • The control unit fetches (gets) the instruction from memory. 
    • The control unit decodes the instruction (decides what it means) and directs that the necessary data be moved from memory to the arithmetic/logic  unit. These first two steps together are called instruction time, or I-time. 
    • The arithmetic/logic unit executes the arithmetic or logical instruction. That is, the ALU is given control and performs the actual operation on the data. 
    • Thc arithmetic/logic unit stores the result of this operation in memory  or in a register. Steps 3 and 4 together are called execution time, or E-time.
  • irects memory to release the result to an output device or a secondary storage device
  • synchronize all computer operations.
  • designed to understand a specific group of instructions called the instruction set
  • identified by an address
  • symbolic address

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• 

  danielyeechankim
  • (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions
  • CPU interacts closely with primary storage, or main memory, referring to it for both instructions and data
  • computer's memory holds data only temporarily, at the time the computer is executing a program.
  • econdary storage holds permanent or semi-permanent data on some external magnetic or optical medium
  • control unit of the CPU contains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • t directs other parts of the system to do so
  • must communicate with both the arithmetic/logic unit and memory.
  • arithmetic/logic unit (ALU) contains the electronic circuitry that executes  all arithmetic and logical operations.
  • perform four kinds of arithmetic operations,
  • performs logical operations

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  brendan_liebross
  • omputer does its primary work in a part of the machine we cannot see
  • secondary
  • Primary
  • wo types of storage
  • ontains circuitry that uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • electronic circuitry that executes  all arithmetic and logical operations.
  • performs logical operations.
  • are equal
  • two values
  • determine if one is less than another
  • determines if one value is greater than another
  • computer can simultaneously test for more than one condition
  • Registers are temporary storage areas for instructions or data
  • collects the result
  • keeps track of where a given instruction or piece of data is stored in memory
  • temporarily holds data
  • used  for several functions
  • Memory is also known as primary storage
  • RAM (Random Access Memory)
  • holds data and instructions for processing
  • Most types
  • only store items while the computer is turned on
  • After being processed, the information is sent to memory, where it is hold until it is ready to he released to an output unit.
  • The process of making the salad
  • we may see disks disappear as an internal storage device
  • most computers today can execute only one instruction at a time
  • execute it very quickly
  • Many personal computers can execute instructions in less than one-millionth of a second
  • Each type of central processing unit is designed to understand a specific group of instructions
  • program manipulates data in memory

  28 more annotations...

• 

  leedaosman
  • Central Processing Unit
  • Secondary Storage
  • Central Processing Unit (CPU)
  • control center that converts data input to information
  • highly complex,  extensive set of electronic circuitry that executes stored program instructions.
  • central processing unit (CPU
  • Primary
  • secondary storage
  • CPU interacts closely with primary storage, or main memory, referring to it for both instructions and data.
  • Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium.
  • computer's memory holds data only temporarily
  • The Control Unit
  • uses electrical signals to direct the entire computer system to carry out, or execute, stored program instructions.
  • The Arithmetic/Logic Unit
  • performs logical operations
  • logical operation is usually a comparison.
  • Equal-to condition.
  • Less-than condition.
  • Greater-than condition.
  • Registers are temporary storage areas for instructions or data. They are not a part of memory;
  • • • An accumulator, which collects the result of computations. 
      • An address register, which keeps track of where a given instruction or piece of data is stored in memory. Each storage location in memory is identified by an address, just as each house on a street has an address. 
      • A storage register, which temporarily holds data taken from or about to be sent to memory. 
      • A general-purpose register, which is used  for several functions.  
       

        

    • Memory and Storage
  • primary storage, primary memory, main storage, internal storage, main memory, and RAM (Random Access Memory);
  • chief characteristic of memory is that it allows very fast access to instructions and data, no matter where the items are within it.
  • secondary (disk) storage. It can store high volumes of veggies for long periods of time
  • Now for a more technical example. let us look at how a payroll program uses all three types of storage. Suppose the program calculates the salary of an employee. The data representing the hours worked and the data for the rate of pay are ready in their respective registers. Other data related to the salary  calculation-overtime hours, bonuses, deductions, and so forth-is waiting nearby in memory. The data for other employees is available in secondary storage. As the CPU finishes calculations about one employee, the data about the next employee is brought from secondary storage into memory and eventually into the registers.
  •           

    Storage	Speed	Capacity	Relative Cost ($)	Permanent?
    Registers	Fastest	Lowest	Highest	No
    RAM	Very Fast	Low/Moderate	High	No
    Floppy Disk	Very Slow	Low	Low	Yes
    Hard Disk	Moderate	Very High	Very Low	Yes
  • Modern computers are designed with this hierarchy due to the characteristics listed in the table.
  • program instructions and data must be placed into memory from an input device or a secondary storage device
  • control unit fetches (gets) the instruction from memory.
  • control unit decodes the instruction (decides what it means) and directs that the necessary data be moved from memory to the arithmetic/logic  unit. These first two steps together are called instruction time, or I-time.
  • control unit eventually directs memory to release the result to an output device or a secondary storage device.
  • Each central processing unit has an internal clock that produces pulses at a fixed rate to synchronize all computer operations. A
  • location in memory for each instruction and each piece of data is identified by an address.
  • memory location can hold only a fixed amount of data; an address can hold only a fixed number of bytes - often two bytes in a modern computer.

  32 more annotations...

• 

  Dan Cooper
  • a control center that converts data input to information output. This control center, called the central processing unit (CPU)
• 14 Apr 16
  

  dh11381
• 21 Mar 16
  

  souravk
  • The computer does its primary work in a part of the machine we cannot see, a control center that converts data input to information output. This control center, called the central processing unit (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions.
  • The CPU interacts closely with primary storage, or main memory, referring to it for both instructions and data. For this reason this part of the reading will discuss memory in the context of the central processing unit.
• 12 Jan 16
  

  Suzumi H

  How the computer works

  Computer works function

• 02 Dec 14
  

  Josephine S

  "
  
  Figure 0: Inside The Computer
  "

  computer CPU diagrams

• 12 Nov 14
  
  • • The Central Processing Unit: 
      • (CPU),  
      • Buses,  
      • Ports and controllers, 
      • ROM; 
       
    • Main Memory (RAM); 
    • Input Devices; 
    • Output Devices; 
    • Secondary Storage; 
       
      • floppy disks, 
      • hard disk, 
      • CD-ROM 
       
       
  • computer does its primary work in a part of the machine we cannot see, a control center that converts data input to information output. This control center, called the central processing unit (CPU), is a highly complex,  extensive set of electronic circuitry that executes stored program instructions.
  • Computers use two types of storage: Primary storage and secondary storage. The CPU interacts closely with primary storage, or main memory, referring to it for both instructions and data. For this reason this part of the reading will discuss memory in the context of the central processing unit. Technically, however, memory is not part of the CPU.
  • omputer's memory holds data only temporarily, at the time the computer is executing a program. Secondary storage holds permanent or semi-permanent data on some external magnetic or optical medium. The diskettes and CD-ROM disks that you have seen with personal computers are secondary storage devices, as are hard disks.
  • e control unit does not execute program instructions; rather, it directs other parts of the system to do so.
  • arithmetic/logic unit can perform four kinds of arithmetic operations, or mathematical calculations: addition, subtraction, multiplication, and division. As its name implies, the arithmetic/logic unit also performs logical operations. A logical operation is usually a comparison. The unit can compare numbers, letters, or special characters. The computer can then take action based on the result of the comparison. This is a very important capability. It is by comparing that a computer is able to tell, for instance, whether there are unfilled seats on airplanes, whether charge- card customers have exceeded their credit limits, and whether one candidate  for Congress has more votes than another.
  • Memory is also known as primary storage, primary memory, main storage, internal storage, main memory, and RAM (Random Access Memory); all these terms  are used interchangeably by people in computer circles. Memory is the part of the computer that holds data and instructions for processing. Although closely associated with the central processing unit, memory is separate from it. Memory stores program instructions or data for only as long as the program they pertain to is in operation. Keeping these items in memory when the program is not running is not feasible for three reasons: 
     
     
    • Most types of memory only store items while the computer is turned on; data is destroyed when the machine is turned off. 
    • If more than one program is running at once (often the case on large computers and sometimes on small computers), a single program can not lay exclusive claim to memory. 
    • There may not be room in memory to hold the processed data. 
  • The chief characteristic of memory is that it allows very fast access to instructions and data, no matter where the items are within it. We will discuss the physical components of memory-memory chips-later in this chapter. 

  • The following table summarizes the characteristics of the various kinds of data storage in the storage hierarchy. 
     

               

    Storage	Speed	Capacity	Relative Cost ($)	Permanent?
    Registers	Fastest	Lowest	Highest	No
    RAM	Very Fast	Low/Moderate	High	No
    Floppy Disk	Very Slow	Low	Low	Yes
    Hard Disk	Moderate	Very High	Very Low	Yes

      Modern computers are designed with this hierarchy due to the characteristics listed in the table. It has been the cheapest way to get the functionality. However, as RAM becomes cheaper, faster, and even permanent, we may see disks disappear as an internal storage device. Removable disks, like Zip disks or CDs (we describe these in detail in the online reading on storage devices) will probably remain in use longer as a means to physically transfer large volumes of data into the computer. However, even this use of disks will probably be supplanted by the Internet as the major (and eventually only) way of transferring data. Floppy disks drives are already disappearing: the new IMac Macintosh from Apple does not come with one. Within the next five years most new computer designs will only include floppy drives as an extra for people with old floppy disks that they must use.

  7 more annotations...

• 18 Sep 14
  
  • Each type of central processing unit is designed to understand a specific group of instructions called the instruction set. Just as there are many different languages that people understand, so each different type of CPU has an instruction set it understands. Therefore, one CPU-such as the one for a Compaq personal computer-cannot understand the instruction set from another CPU-say, for a Macintosh.
• 13 Feb 14
  

  Bob Calder

  computer CPU howstuffworks

• 22 Dec 13
  

  Shyam Patel
  • As its name implies, the arithmetic/logic unit also performs logical operations.
  • A logical operation is usually a comparison. The unit can compare numbers, letters, or special characters.
  • The computer can then take action based on the result of the comparison. This is a very important capability.

  1 more annotation...

• 09 Apr 13
  

  Matthew Marshall

  INTROCHAP4

• 29 Jan 13
  

  Mrs Greer MSJ ICT

  technology computer CPU howstuffworks

• 03 Oct 12
  

  Sub Proletarian

  computer CPU Logic gate

• 07 Sep 12
  

  Deb Rottinger

  java cpu

• 04 Aug 12
  

  Chris

  sdsc cpu

• 16 Mar 12
  

  Rosemary Miller

  technology computer cpu howstuffworks computers networks tutorial

• 03 Mar 12
  

  daniela attard

  cpu

• 25 Jan 12
  

  paul rayner

  computer_science

• 11 Dec 11
  

  geraldsjackson

  How Computers Work: The CPU and Memory

  programming technology computer

• 28 Oct 11
  

  anthony crowther

  Conceptualization
  

  computer_links technology

• 22 Oct 11
  

  Jacob Platin

  A continuation of the first site

  technology information microprocessors computer CPU

• 17 Nov 10
  

  Bino Cular

  cpu ram

• 15 Nov 10
  

  Brittany M
  • 
• 14 Oct 10
  

  Danny Mackenzie

  Technology

• 12 Oct 10
  

  Rexanna Sanders

  computer HowComputersWork memory CPU resources education

• 

  skip zalneraitis

  computer technology how

• 11 Oct 10
  

  Peter McAsh

  computer howstuffworks icsxx ics2o dcvi

• 

  Damianne President

  computer technology howstuffworks

• 

  Doug Peterson

  This part of the reading will examine the CPU, Buses, Controllers, and Main Memory. Other sections will examine input devices, output devices, and secondary memory.

  computer technology

• 27 Sep 10
  

  K Ishtiaq

  CPU

• 12 Dec 08
  

  Andrew Barker

  techfound computerConcepts

• 03 Feb 06
  

  Lisa Raines

  technology education computer

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