Unix System Administration Computer Hardware ISA Jar Binks

Unix System Administration Computer Hardware

ISA Jar Binks, ISA Annoying • Industry Standard Architecture • Original PC Bus • 8 -bit ISA (1980) – 8. 3 MHz bus speed – 7. 0 Mbytes per second • 16 -bit ISA – 8. 3 MHz bus speed – 15. 9 Mbytes per second

Microchannel? Narrow Urethra? • “IBM proprietary” bus meant to extend the ISA bus • Primarily used in PS/2 and RS/6000 computers • 8, 16, 32 -bit transfers • Introduced concept of “bus mastering” and “plug and play” • Not widely implemented and was rivaled by the EISA bus architecture

EISA, Wanna Buy a Vowel? • Originated in 1988 & 1989 by the “Gang of Nine” - AST, Compaq, Epson, HP, NEC, Olivetti, Tandy, Wyse & Zenith • Designed as alternative to microchannel • EISA connectors are a superset of ISA, so both EISA and ISA card will work in the same slot • Bus mastering, shared interrupts • 32 -bits, 8. 3 MHz, 31. 8 Mbytes/sec

Take the SBUS Downtown • Developed by Sun for its new SPARCstation systems in 1989 • Existing ISA and EISA weren’t powerful enough • Today, Sun is moving to the PCI Bus • However, SBUS I/O throughput is often 3050% faster than PCI implementations • Over 3 million SBUS slots are in use today • SBUS is an IEEE standard

VLB - Very Large Band-aid? • VESA Local Bus • Created to help solve the need for large video transfers created by emerging graphical applications (e. g. Windows) • Separate faster bus to augment the ISA bus. • VL bus put on processors faster memory bus, or “local” to the processor. • VL slots accept both VL & ISA cards • 32 -bit, 33 MHz, 127. 2 Mbytes/sec

PCI - Backwards, I C P • Successor to VLB, EISA, Microchannel and SBUS • Tends to co-exist with ISA still today • Supports, bus mastering, shared interrupts, plug-n-play • PCI - 32 -bits, 33 MHz, 127. 2 Mbytes/sec • PCI 2. 1 -64 -bits, 66 MHz, 508. 6 Mbytes/sec • New 100 MHz bus support too!

Plug ‘n Pray • Plug-n-Play was designed to make it easier for to install PC cards • Macs and Suns had a type of play-n-play from their inception • Eliminated the need to set dip switches or jumpers on the expansion card • ISA cards were retrofitted with a type of plug-n-play

Interface cards: SBUS, ISA (16), PCI (32), MCA(16), EISA

Let’s Get Graphic! • AGP - Accelerated Graphics Port • 32 -bits wide (same as PCI) • Runs at full bus speed of 66 MHz (PCI runs at 1/2 bus speed). • Minimum of 254. 3 Mbytes/sec • 2 X and 4 X mode for faster data transfer • 4 X = 1, 017 MB/sec, but theoretical 100 MHz bus limit is 763 MB/sec.

That’s UPA, not UPE • • • UPA - Ultra Port Architecture Peak rate of 1. 3 GBytes/sec Packet switching instead of a bus Unlimited number of buses per system Can tie together other, commodity buses such as PCI • Example: Sun Ultra Enterprise 450 has 6 PCI buses managed by a UPA

1+1 Does Not Always Equal 2 • Calculating bandwidth • ( bit-width/8 ) * ( bus-speed ) * (1, 000/1, 048, 576 ) = MBytes/second • ( 32 bits / 8) * (33. 3 MHz) * (1, 000/1, 048, 576) = 127. 2 Mbytes/second • “M” in MHz = 1, 000 (10^6) • “M” in Mbytes = 1, 048, 576 (2^20)

I Seemed to Have Lost Some Memories. Oh, There They Are.

What Was I Talking About? Oh Yeah, Memory. • DRAM - centipede memory chips • SIMM – 30 pin, 72 pin – ECC, EDO, FPM • DIMM – 168 pin – SDRAM, PC 100 • RDRAM – 184 pin RIMM – 600 -800 MHz

Can You Factor the Form • AT, Baby-AT • ATX, mini-ATX • LPX, mini-LPX, NLX

Have you hard the one about… • Hard drive technology – MFM - Modified FM – RLL - Run Length Limited – ESDI - Enhanced Small Device Interface – SCSI - Small Computer – IDE - Integrated Drive Electronics

Muth Freakin Monster • Modified Frequency Modulation • Early drive type - more “compact” encoding scheme than FM (reduced redundant cycles by considering previous bit encoding) • Appx 2 X capacity of FM • Used on floppies - “double density” • Drives had no processing electronics onboard

Requires Lotsa Luck • Run Length Limited • Modified encoding scheme again, associating flux patterns with bit sequences - appx 30% increase over MFM • Family of techniques: – PRML - permits weaker field strengths for higher areal density [track-to-track and linear] - flux reversals harder to detect - use DSP (30 -40% increase in density) – EPRML - even higher densies (linerarly) using enhanced DSP - 20 to 70% increase (THIS IS USED TODAY)

Extra Stupid Development Initiative? • Enhanced Small Device Interface • Attempt to improve MFM/RLL interfaces • Short-lived due to SCSI/IDE release

Itsa Device Explosion!! • Integrated Drive Electronics - drive unit contains all interface electronics required. Attaches directly to system bus • Two devices per channel, two channels per system, device communication monopolizes the channel, length limits on cable • High system resource requirements due to direct interaction with system bus

Who you callin SCSI? • • • Small Computer System Interface Supports higher device counts and longer cable lengths Performance high for large numbers of devices Permits command queuing and reordering Separate bus and controller, offloads management and transfer functions from CPU • High cost • All devices can be targets or initiators (yes, even the PC)

You Are Elle’s • Hardware Specs – http: //www. techfest. com/hardware/ http: //www. pcguide. com/ • Sun UPA Spec – http: //www. sun. com/microelectronics/ whitepapers/wp 95 -023. html

Wake Up! • What does PCI stand for? • What cards other than graphics cards fit in the AGP slot? • Why would Sun switch to PCI bus if SBUS can attain 30 -50% better I/O throughput?