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In this week's lesson on Computer Architecture, we explore essential concepts related to external memory. Topics include the structure and performance of magnetic disks, optical memory, and magnetic tapes. Key terms like seek time, spindle speed, and access time will be defined. We will review the major functions of I/O modules and how they manage communication between internal resources and external devices. This session aims to enhance your understanding of how data is processed and transferred within computer systems. Don't miss the quiz that will test your knowledge!
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Input / OutputWeek 6 Computer Architecture Computer Architecture
Review External Memory • English words & ideas you must know: • Head • Sector • Track • Cylinder • Platter • Seek-Time • Spindle • Spindle Speed • RPM (Revolutions Per Minute) • Rotational delay • Access time • CAV (Constant Angular Velocity) • CLV (Constant Linear Velocity) • Spiral Computer Architecture
What we will learn today • Collect Homework • Review last class • Input / Output • External Devices • I/O Modules • QUIZ Computer Architecture
External Memory • Magnetic Disk • Hard Disk • Floppy • Optical Disk • CD-ROM, CD-R, CD-RW • DVD • Magnetic Tape Computer Architecture
Magnetic Disk Performance • Capacity • Seek Time (Minimum / Average) • Spindle Speed • Average Rotational delay • Maximum transfer rate • Bytes / sector • Sectors / track • Tracks / cylinder • Cylinders Computer Architecture
Example • Read 400 KB file • Average seek time – 7 ms • 1024 Bytes / sector; 200 Sectors / track • Rotational Speed – 15,000 rpm Computer Architecture
Optical Memory • CD-ROM (compact disk – read only memory) • No concentric circles (like hard disk) – spiral track • CLV – Constant Linear Velocity • CAV – Constant Angular Velocity • Block format • 12 Bytes – SYNC • 4 Bytes – ID • 2048 Bytes – Data • 288 Bytes - ECC (Error Correcting Code) Computer Architecture
Magnetic Tape • Sequential Access • Parallel Tracks • 9, 18, 36 tracks • Recording • Parallel recording • Serial Recording • Serpentine recording Computer Architecture
External Devices • Human readable • Printer • Video Display (Monitor) • Machine readable • Hard Drive / Floppy • CD-ROM • Communications • Networking Computer Architecture
External Devices - Connections • System Bus • I/O Module • External device • Controller • Device Computer Architecture
I/O Modules • Functions • Control and Timing • Processor Communication • Device Communication • Data Buffering • Error Detection Computer Architecture
Control and Timing • Coordinate the flow of traffic between internal resources and external devices • Main memory • System bus • Processor time Computer Architecture
Processor Communication • Command decoding • Data • Status reporting • Address recognition Computer Architecture
Device Communication • Commands • Status information • Data Computer Architecture
Data Buffering • Essential task!! • Used to match speed differences • Data can be sent / received in a burst • Less interrupts Computer Architecture
Error Detection • Mechanical errors • Electrical errors • Software errors • Usually has Error Detection Code Computer Architecture
I/O Module Structure Data linesDataStatus Control Address Lines Control Lines Data Registers External Device Logic Status Registers External Device Logic I/O Logic Computer Architecture
What you know now • Input / Output • External Devices • I/O Modules Computer Architecture
Reading • http://en.wikipedia.org/wiki/Input/output • http://en.wikipedia.org/wiki/Port-mapped_I/O Next Lecture • Input / Output - Continued Computer Architecture
Reading Next Lecture • Input / Output - Continued Computer Architecture
Self-PreparationStudy GuideWeek 6 1. What are the major functions of an I/O Module?2. What are three broad classifications of external, or peripheral, devices?3. What is buffering? Why is it important? Computer Architecture
