A computer system consists of hardware, system programs, and application programs figs 7

THE NATURE OF THE DESIGN PROBLEM 12.2 INTERFACE DESIGN 12.3 IMPLEMENTATION 12.4 PERFORMANCE 12.5 PROJECT MANAGEMENT 12.6 TRENDS IN OPERATING SYSTEM DESIGN 12.7 SUMMARY

7.4 MULTIMEDIA PROCESS SCHEDULING

7.5 MULTIMEDIA FILE SYSTEM PARADIGMS

1 2 3 4 5 6 7 8

The next fieldstarts here

Scan line painted

on the screen

Horizontalretrace

Verticalretrace

Fig 7-5 The scanning pattern used for NTSC video and sion.

2 1 4 1 0 0 0 0

1 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

DCT Coefficients

150 92 26 3 1 0 0 0

80 75 19 2 0 0 0 0

20 18 13 2 0 0 0 0

4 3 2 1 0 0 0 0

1 1 1 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

Quantized coefficients

1 1 2 4 8 16 32 64

1 1 2 4 8 16 32 64

2 2 2 4 8 16 32 64

4 4 4 4 8 16 32 64

8 8 8 8 8 16 32 64

16 16 16 16 16 16 32 64

32 32 32 32 32 32 32 64

64 64 64 64 64 64 64 64Quantization table

Fig 7-8 Computation of the quantized DCT coefficients.

20 18 13 2 0 0 0 0

4 3 2 1 0 0 0 0

1 1 1 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

Fig 7-9 The order in which the quantized values are transmitted.

Fig 7-10 Three consecutive video frames.

A1

A1

B1B1

A2

A2A2

C2C2

C2

C3C3C3

Fig 7-12 An example of RMS and EDF real-time scheduling.

A1

B1B1

Fig 7-14 (a) A pull server (b) A push server.

Frame 9000 instream 3 is sent

at 8:20 min

TimeStream

Fig 7-15 Near video on demand has a new stream starting at ular intervals, in this example every 5 minutes (9000 frames).

Play point at 12 min

Play point at 75 min

Play point at 15 min

Play point at 16 min

Play point at 22 min

Fig 7-16 (a) Initial situation (b) After a rewind to 12 min.

(c) After waiting 3 min (d) After starting to refill the buffer.

(e) Buffer full.

Video A A A T T Video A A A T T Video A A A T T

Frame 3Frame 2

Frame 1

Audio

track

Texttrack

Fig 7-17 Interleaving video, audio, and text in a single ous file per movie.

contigu-Disk block largerthan frame

AudioTextI

II

0 9000 18000 27000 36000 45000 54000 63000 72000 81000 207000

Stream

24

Stream 23

Stream 15

Stream 1

Order in which blocks are read from disk

Fig 7-19 Optimal frame placement for near video on demand.

Fig 7-20 The curve gives Zipf’s law for N = 20 The squares

represent the populations of the 20 largest cities in the U.S., sorted

on rank order (New York is 1, Los Angeles is 2, Chicago is 3, etc.).

10

Movie8

Movie6

Movie4

Movie2

Movie1

Movie3

Movie5

Movie7

Movie9

Movie11Cylinder

Fig 7-21 The organ-pipe distribution of files on a video server

D0D1D2D3D4D5D6D7(a)

A0A4B0B4C0C4D0D4

A1A5B1B5C1C5D1D5

A2A6B2B6C2C6D2D6

A3A7B3B7C3C7D3D7(b)

A2A6B1B5C0C4D3D7

A3A7B2B6C1C5D0D4(c)

A0A6B3B4C0C7D1D6

A2A5B1B7C2C6D2D5

A1A4B2B5C3C4D3D4

A3A7B0B6C1C5D0D7(d)

10 sec 1 min 2 min 3 min 4 min

0

1800

3600

54001

800

3600

5400

72007200

3600

5400

7200User 1

7200

1800

36000

Fig 7-23 (a) Two users watching the same movie 10 sec out of sync (b) Merging the two streams into one.

Order in which disk requests are processed

Buffer for odd frames

Buffer for even frames

Block requested

Fig 7-24 In one round, each movie asks for one frame.

Requests (sorted on deadline)