LAST MINUTES NOTES


OPERATING SYSTEM

  • Throughput= one measure of work is the no. Of processes completed per time unit
  • Turn around time= time of submission between time of completion
  • Waiting time= some of periods spent waiting in the ready queue
  • Response time= submission of request until the first response
  • Convoy effect= all the i/o processes end up waiting in the ready ueue until the cpu bound process is done
  • CRITICAL SECTION = PROCESSES IS MUTUALLY EXCLUSIVE IN TIME
  • Solution of critical section is semaphores= wait – and signal ++
  • Request edge= p->r
  • Assignment edge= r->p
  • Logical address is generated by CPU
  • Physical address is generated by MAIN MEMory
  • SJF is optimal than FCFS
  • Fragmentation
  • External= when process remove from memory , the free memory space broken into little pieces.
  • Solution of external fragmentation is COMPACTION
  • Internal fragmentation= mem. That is partitioned nut is not being used
  • Paging
  • Demand paging is similar paging with swapping
  • Pure demand paging = no page in the memory

NETWORKING

  • MODEM= 28 KBPS TO 56kbps
  • Broadband 18kbps to 500kbps
  • DSL= 54kbps to 1000kbps
  • NIC,ETHERNET CARD, LAN CARD all are same and it will RJ 45 connenctor
  • RJ MEANS REGISTERED JACK
  • FTP follows RFC 959 standard
  • Bridges= separate single n/w into segments
  • 25 is physical, frame, packet level
  • Clustering of data= selg organzing map and 1/n size
  • Dijkastra = RIP and IGRP
  • Link state= common database
  • Class a private address
  • 0.0.0 through 10.255.255.255
  • Class b
  • 16.0.0 through 172.31.255.255
  • Class c
  • 168.0.0 through 192.168.255.255
  • Physical layer uses repeater, bits
  • Datalink uses bridges, frames
  • n/w uses routers, packets
  • presentation uses data encryption
  • transport uses end to end
  • two type of access control= standard and extended
  • wlan IEEE specification upto 54mbps at 2.4ghz
  • IEEE 802.11G with top speed
  • CDMA uses 18 cells
  • Ppp use to identify the n/w layer protocol
  • NCP is used to identify
  • DHCP use at Transport layer
  • Hub is specified in OSI physical
  • Protocol used to send destination n/w message back to host
  • ICMP uses PING
  • BPDU sent from layer2 device every 2 sec
  • PPP provides addressing, authentication
  • LAN break up broadcast domains at layer 2
  • 1Q, ISL= used to configure trunking on a port
  • Gateway greatest used in no. of layers
  • UDP= DHCP , SNMP, TFTP
  • Highest layer transmit data application
  • ARP used to find hardware address
  • Both tcp and udp is DNS
  • RIPV2 is used classless routing
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