Architecture of the CPU

Architecture of the CPU

1. CPU

   • (ALU) Artihmetic logic unit
     • the ALU basically does all the calculatons
     • completes all simple addition and subtrcton
     • it performs logic operations such as and, or and not. and binary shift
     • it contains the accumulator register
   • control unit (CU)
     • the control unit is in overall control of the CPU. its main job is to manage the fetching, decoding and execution
     • it controls the flow of data inside the cpu and outside the CPU
   • Cache
     • the cache is very fast memory in the CPU. its slower than the registers but faster than ram
     • it stores regularly used data so that the CPU can access it quickly the next time its needed
     • Cache have very low capacity and are expensive compared to ram and secondary storage
     • there are different levels of cashe memory L1 L2 L3. L1 is the quickest but has the lowest capcity
   • Von Neumann Architecture
     • MAR
       • holds any memory address about to be used by the cpu. the address might point to data or a cpu instruction
     • MDR
       • the memory data register holds the actual data or instruction. This may have been fetched from memory, or be waiting to be written to memory

2. Protocol layers

   • Protocols
     • TCP/IP
       • communication over a LAM/WAN
     • HTTP
       • Web Page Requests
     • HTTPS
       • Web Page Requests
     • FTP
       • File Transfers
     • POP3
       • email
     • IMAP
       • Email
     • SMTP
       • email