Binghamton

University

CS-311

Fall 2020

1

Binghamton

University

CS-311

Fall 2020

Motherboard

• The main printed circuit board in your computer

• Contains (typically)• CPU (Microprocessor Chip)

• RAM/ROM chips

• Power Management

• Cooling Fan

• Slots for Hard Drives

• Network Connection ports

• Busses to carry data between everything

• Expansion slots to add new stuff

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Binghamton

University

CS-311

Fall 2020

What More?

3

RAM

Binghamton

University

CS-311

Fall 2020

Typical Peripheral Devices

• Persistent Memory• Paper Tape, Punch Cards, Tape Drives, Disk drives, USB drives, Cloud storage

• Input from User• Text: Punch Cards, Keyboard, Microphone (Speech to Text)• Location: Mouse, Joystick, Touchpad, Touchscreen, Video Camera• Audio/Visual: Microphone, Video Camera

• Output to User• Text: Printer, Teletype, Monitor• Audio/Visual: Graphics Printer, Monitor, Speaker, earphones, VR Goggles

• I/O to the rest of the world• Modem, ethernet, WWW, IOT (Thermostat, Refrigerator, … )

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Binghamton

University

CS-311

Fall 2020

Categorizing Peripherals

Input From User Output to User Persistent Memory Network

Human Readable Keyboard Printer, Monitor Punch cards?, Scanned documents?

Machine Readable* Mouse, Game controller

Disk Drives, USB drives,

Modem, ethernet

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*Textbook also has "communication", but communication is a subset of Machine Readable.

Chap 11.1

Binghamton

University

CS-311

Fall 2020

Data Rate Variance

6

Binghamton

University

CS-311

Fall 2020

Device I/O Basics: Stream I/O

• A one directional ordered list of bytes• Input Stream or Output Stream

• Ordering is almost always by time

• Timing is "Asynchronous" – independent from CPU cycles

• Transmission is typically serial – 1 bit at a time

• Need 8 bits to read or write 1 byte• Internally, use an 8-bit bus

• Extra bits may be used for control signals

• A stream may be "open" or "closed"

7

Binghamton

University

CS-311

Fall 2020

Early Peripherals: Tape Drives

8

• Required manual mounting of tape

• Good sequential access• Slow "direct" access• Origin of the "stream" of

bits/bytes concept

Binghamton

University

CS-311

Fall 2020

Early Peripherals: Teletype

9

• Two Streams:• User types – input stream• Computer types – output

stream• User data not sent until "enter"• Prototype for "terminal window"

By ArnoldReinhold - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31105488

Binghamton

University

CS-311

Fall 2020

Device I/O Basics: Ports

• A "port" is a place where data from the outside world can be delivered to or from your computer

• Typical ports on a PC include:• VGA (Video Graphic Array) – 15 pin analog graphic interface

• Serial Port – 9 pin old interface for printers – 1 bit at a time ~100kbps

• Parallel Port – 25 pin interface – multiple bits at a time ~150kbps

• USB – Universal Serial bus port - ~14mbps, may include power

• Ethernet – 10mbps – 100mbps based on network bandwidth

• Others: Speaker/Earphone, microphone, power, etc.

10

Binghamton

University

CS-311

Fall 2020

Device I/O Basics: Block (Buffered) I/O

• A one directional ordered list of blocks of bytes• block size is a multiple of bytes

• Input or Output

• Ordering is almost always by time

• Timing is "Asynchronous" – independent from CPU cycles

• Think of as a "stream" of blocks of bytes

11

Binghamton

University

CS-311

Fall 2020

Stream to Block

12

Stream byte

64 byte buffer

Binghamton

University

CS-311

Fall 2020

Stream to Block

13

Stream

block

byte

64 byte buffer

Binghamton

University

CS-311

Fall 2020

Block to Stream

14

Streamblock

byte

byte

64 byte buffer

Binghamton

University

CS-311

Fall 2020

Hard Drive Technology

15

• Moving away from the concept of "mountable" storage

• "Direct" access – every byte is less thanone rotation away

• Almost always used to "stream" data• More reliable than tape

Binghamton

University

CS-311

Fall 2020

I/O Evolution : Phase 1

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Device CPU Memorybus

data

control

Chap 11.2

Binghamton

University

CS-311

Fall 2020

I/O Evolution : Phase 2

17

Device CPU Memorybus

data

control

Binghamton

University

CS-311

Fall 2020

I/O Evolution : Phase 3

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Device CPU Memorybusdata

control

Interrupt

Binghamton

University

CS-311

Fall 2020

I/O Evolution : Phase 4

19

Device CPU Memorybus

control

Interrupt

Binghamton

University

CS-311

Fall 2020

I/O Evolution : Phase 5

20

Device CPU Memorybus

control

Interrupt

Binghamton

University

CS-311

Fall 2020

I/O Evolution : Phase 6

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Device CPU Memorybus

control

Interrupt

Binghamton

University

CS-311

Fall 2020

I/O Organization : Logical vs. Physical

Logical

• High level user friendly:open/close/read/write/seek

• Same for every device

• Just a few system calls

• Synchronous blocking

• Abstract dir/file concepts

Physical

• Low level physical device commands

• Different for each device

• ↑ device cmds per system call

• Asynchronous interrupts

• Concrete disk addr/block

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Chap 11.4

Binghamton

University

CS-311

Fall 2020

Other Topics

• I/O Buffering

• Asynchronous I/O Models

• Disk Cache

• Disk Scheduling

• Files • File Management Systems• Directories• Protection/Sharing/Record blocking• File Organization / access• Secondary Storage Mgmt• UNIX/Linux inodes

• Error Detection and Correction

• RAID

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Chap 12

Chap 11.4-9