CPU Computer Hardware Organization (How does the computer look from inside?) Register file ALU PC System bus Memory bus Main memory Bus interface I/O bridge I/O bus Expansion slots for other devices such as network adapters USB controller Graphics adapter Disk controller Mouse Keyboard Display Disk Executable (machine language) program stored on disk 4/22/2017 Introduction to Computer Science

Introduction to Computer Science 4/22/2017 Introduction to Computer Science

Computer Hardware – Buses Electrical conduits connecting computer components Transport bytes of information back and forth between components Designed to transfer chunks of bytes called words The number of bytes in a word (word size) is a fundamental system parameter For example, Intel Pentium systems have a word size of 4 bytes (32 bits) 4/22/2017 Introduction to Computer Science

Computer Hardware - I/O devices The computer system’s connection to the external world Examples, Keyboard(I), mouse(I), Screen(I), disk drive (I and O) Each I/O device connects to the bus by a controller or an adaptor. A Controller is a chip set in the device itself, or on the system’s main board (motherboard) An Adaptor is a card that plugs into a slot on the motherboard Purpose of controller or adaptor is to over see the transfer bits back an forth the I/O bus and the I/O device. 4/22/2017 Introduction to Computer Science

Computer Hardware – Main Memory(MM) MM is a temporary storage device (in what way temporary?) and connection to the external world Holds both a program and its data which the program manipulates while the processor is executing the program Physically, MM consists of a collection of Dynamic Random Access Memory (DRAM) chips. Logically, MM is organized as a linear array of bytes, each with its own unique address. The only operations MM understands is to read (transfer bytes from an address to CPU), or to write (transfer bytes from the CPU to a given address) 4/22/2017 Introduction to Computer Science

Computer Hardware – Processor (CPU) The Central Processing Unit (CPU) interprets instructions stored in MM Among other things contains the following: Program Counter (PC), a register that contains the address the next program instruction. Registers, a collection of small storage devices – both special and general purpose. Arithmetic/Logic unit (ALU), computes new data and address values (think of it as the calculator of the computer) 4/22/2017 Introduction to Computer Science

Computer Hardware – Processor (CPU) 4/22/2017 Introduction to Computer Science

Computer Hardware –CPU Process FETCH - Read from MM the instruction (bits) whose address is in PC register. DECODE - Interpret the bits in the instruction. EXECUTE - Perform some simple operation dictated by the instruction. In parallel, update the address in the PC register to the address of the next instruction. 4/22/2017 Introduction to Computer Science

Computer Hardware – CPU Instructions Load: Copy a word from MM into a register. Store: Copy a word from a register to a location in MM. I/O read/write: Copy a word between an I/O device and a register Arithmetic: Add, subtract, multiply, divide. Logic: And, or, not, xor, etc. 4/22/2017 Introduction to Computer Science

Introduction to Computer Science CPU 4/22/2017 Introduction to Computer Science

Introduction to Computer Science Main Memory 4/22/2017 Introduction to Computer Science

Introduction to Computer Science Mother Board 4/22/2017 Introduction to Computer Science

Introduction to Computer Science Printed Circuit Board 4/22/2017 Introduction to Computer Science

Introduction to Computer Science Expansion Slots 4/22/2017 Introduction to Computer Science

Introduction to Computer Science Disk Drive 4/22/2017 Introduction to Computer Science

Introduction to Computer Science Case 4/22/2017 Introduction to Computer Science

Introduction to Computer Science Power Supply 4/22/2017 Introduction to Computer Science