Fs Chapter3

7/31/2019 Fs Chapter3

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File Processing (3) Konkuk University (DB Lab.) 2


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BoomRead/write heads

Spindle

Platters


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Clusternumber Clusterlocation

12

3...

The part of the FAT

pertaining to our file

.

.

.

2

1

3


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file extentsextent

extent

extent


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1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 3 3 3 4 4 4 4 5 5 5

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 3 3 3 4 4 4 4 5 5 5

Sector 1 Sector 2 Sector 3 Sector 4 Sector 5

(a) Sector organization

(b) Block organization (more desirable)


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Countsubblock

Datasubblock

Countsubblock

Datasubblock

Countsubblock

Keysubblock

Datasubblock

Countsubblock

Keysubblock

Datasubblock


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How the byte is stored on a

disk, when a program writea byte to a file on a disk ?


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1

2

3

4

5

Logical layerLogical layer


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6

7

8

9

Physical layerPhysical layer


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FIGURE 3.21 The file manager sends the I/O processor instructions in the from of an I/O

Processor program. The I/O processor gets the data from the system buffer, prepares it on

the disk, then sends it to the disk controller, deposits it on the surface of the disk.

Users program

......

Users data area:

File Manager

.

Invoke I/O processor

.

.

.

I/O processor

Program.

.c: P

p

System

buffer

p

p

p

Disk

controller

I/O processor


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Program data area

Program data area

To disk

To diskI/O buffer 1

I/O buffer 2

I/O buffer 1

I/O buffer 2


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systembuffer

programsdata area

systembuffer

Disk

Diskusers

program location(pointer)

Movemode

Locatemode


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Disk

Disk

Scatterinput

Gatheroutput

readv()

writev()

buffer 1

buffer 2

buffer 1

buffer 3

buffer 2


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I/O system

PROCESSES

KERNEL

User programs Libraries Shell commands

System callinterface

Block I/Osystem(normalfiles)

CharacterI/O system(terminals,printers, etc.)

NetworkI/O system(sockets)

block device drivers

disk disk...

character device drivers

consoles printers...

network interface drivers

...networks...

HARDWARE


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File

descriptor

File table

entry

0 (keyboard)1 (screen)

2 (error)3 (normal)4 (normal)5 (normal)

.

.

.

to open filetable


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R/Wmode

# of

processesusing it

Offset

of nextaccess

ptr to

writeroutine

inode

tableentry......

write 1 100 ......

to inodetable

write()routinefor this typeof file


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devicepermissions

owners useridfile size

block count

fileallocationtable

.

.

.

.

.

.


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