Network Computers

1
Network Computers

• Connection - physical
• Protection - security
• Dissemination effective sharing
• Reliability - redundancy

2
Connection

• BNC
• RJ
• 11 phone
• 45 8 pair
• DB
• 25 RS-232C (or parallel)
• 15 10Base5
• 9 Token Ring (obs)
• Fiber
• SC
• ST
• Not usually to the desktop

3
NICs

• Must match LAN
• Arcnet, Token Ring, Ethernet
• Ethernet Combo cards
• 10Base5 DB15 (AUI) with transceiver to coax
• 10Base2 BNC T-connectors
• 10BaseT RJ45
• XBaseFx fiber SC or ST
• Token Ring DB9 or RJ45
• Lights Connection and Activity

4
Modems

• UART (16550 UART)
• Internal to PC
• RJ 11
• System Resources for Modems NICs
• Needed (p 250)
• IRQ (We need to talk..)
• I/O address
• May need
• DMA not required by NICs nowadays
• Memory Address
• Ports I/O addresses
• Combinations

5
IRQs one device per IRQ
6
I/O Addresses

• Hexidecimal 2 bytes
• examples
• 0060 keyboard
• 0300 NIC

7
DMA Channels
Memory Addresses 4 bytes000A0000- 000AFFFF
8
Data Portal Names, I/O, and IRQsome are mutually
exclusive
9
Modem, NIC Installation

• Physical Connections
• Plug it in
• PCI (current, smaller) - better for NICs
• ISA (older, larger) ok for modem
• System Resources
• PNP?
• Onboard jumpers
• Identify potential free resources.
• Drivers
• Updated, on disk, with Win
• Install Driver, set-up card resources
• Reboot, system resources (Device Manager)

10
Protection

• Backups
• Rarely restored, Emergency
• QIC, DAT, DLT (current)
• Off-site Chapter 11.
• Redundancy
• Drive Mirroring 2drives, one controller
• Drive Duplexing 2 drives, two controllers
• Disk Striping 1file -gt multiple drives
• Without parity no redundancy
• With parity added parity drive can rebuild data
• At least 3 drives.

11
RaidRedundant Array of Inexpensive (Independent)
Disks

• Raid 0 Disk striping
• Raid 1 Disk Mirroring and Duplexing
• Raid 2 Disk striping/multiple parity (rare)
• Raid 3,4 Disk striping with parity
• Raid 5 Disk striping with parity on each drive
• Raid 6 Raid 5 asynch, cached

12
Raid Implementations

• Software
• Firmware/Hardware
• SCSI
• Hot-swapping
• Sector interleaving
• http//www.creativecow.net/articles/lindeboom_ron/
  how_raid_works/index.html

13
Other Protection

• Power
• Dedicated Circuits for Servers
• UPS
• BPS
• Environmental
• Fire
• Flood
• Quake