Computers

• Memory
  • Volitle, or temporary
  • nonvolitle or perminant
  • Can hold 0 or 1, a bunch of times over
  • bit {0,1}
  • byte 8 bits
  • Word - processor dependant, most are 32 - 64 bits
  • Kilobit is about 1000 bits , exactaly 2¹⁰ = 1024 bits
  • Megabit is 2²⁰
  • A gigabit is 2³⁰
  • Substitute byte for bit, and get storage sizes, multiply by 8.
• Cache memory
  • Memory is much slower than the CPU, so there is small fast memory between the two called cache.
  • Sometimes it is split, some for instructions, some for data
  • D-cache, I-cache
  • Sometimes there are more than one layer of cache, this is then L1-cache and L2-cache
• CPU
  • This is what does the actual work.
  • Divided into a number of parts
  • ALU - Arithmetic Logic Unit - does the math
  • Clock
  • CU - Control Unit - decides what to do next
  • MMU - memory management unit - interacts with memory
  • Registers - limited amount of very fast memory
  • Fetch-Execute Cycle
    • CU tells the MMU to get an instruction from memory
    • MMU gives the instruction to the CU
    • CU decodes the instruction
    • CU tells MMU to fetch data if necessairy and send it to ALU
    • CU tells the registers to send data to ALU,
    • ALU does whatever
    • CU tells ALU what to do with the results
  • See me in 312 for a much better description.
  • Many different types, and styles
  • Each has it's own machine language, assembly language
• Secondary storage
  • Disks, zips, floppies, cd, ...
  • Removable or non-removable
  • Attached or perhaps networked
  • Very slow, and inexpensive.
• I/O devices
• Peripheral Devices
  • Everything Else
• Computer Hardware: The physical components of the computer
• Software : the coding that makes things work. The set of instructions.
• PC-Workstations-Mini-Mainframe-Super Computer

Software

• Operating System - A program that manages the resources of the computer
  • What is running on the CPU right now.
  • Who has access to memory, disk, keyboard, ...
  • CSCI 380
• Utilitiies
  • Programs that you need, but aren't the OS Propper
  • Compiler, editor, linker, network software ...
• Sometimes an operating system is both the OS propper and the utilities
• Applications
  • Other programs that are not necessairy for the operation of the computer
  • Web Browse, Word, Excel, Powerpoint ...
• Some things we will care about this semester
  • LINUX-UNIX
    • A family of OSs
    • Brief History
    • LINUX and a very brief history
    • Why linux and not windows?
  • FTP
    • An utility and a protocol
    • Transfer files between computers.
  • Telnet
    • An utility
    • Log onto a remote computer
  • PuTTY
    • A utility
    • Much like telnet, but it works.
    • home page
    • If you plan to work from home, you should get this if you have windows installed.
    • There is also a nice ftp client there as well
  • Editors vs Word Processors
    • The job of a word processor is to make "pretty" documents
    • Different fonts, pictures, text, ...
    • Many people use these for many tasks.
    • Often the results are saved in "strange" formats
    • Usually very sufficsticated.
    • The job of an editor is to put things where you want them
    • And to put what you want there.
    • Usually somewhat primitave in some sense
      • Text based, not wysiwyg
      • Keystrokes, limited mouse ability
    • There are large number of editors available in *NIX
      • ed, vi, ... the original
      • emacs
      • joe
    • joe
      • source code
      • Some useful documentation is here
    • For a programmer, an editor is a basic tool, it is much like a hammer for a carpenter.
    • You should learn how to use your editor, it will take some time, but it will be well worth the investment.
• Compilers
  • We will use g++
  • This is installed on our linux machine (cslab41)
  • It is fairly standards compliant
  • But your code must run on cslab41.
  • So if you develop your code in VisualC (or anything else) it must run on cslab41.
• Open Source to Commercial Software

A quick history of C, C++

• BCPL or B
• C, AT&T Bell Labs, Dennis Richie
• ANSI C
• x++ add one to x.
• Object Oriented
• Bjarne Stroustrup, AT&T Bell Labs
• C++
• ANSI C++
• A word on standards