Scalable Continuous Media Streaming Systems in .NET

Making QR-Code in .NET Scalable Continuous Media Streaming Systems
Scalable Continuous Media Streaming Systems
Recognize QR Code 2d Barcode In .NET
Using Barcode Control SDK for .NET framework Control to generate, create, read, scan barcode image in .NET framework applications.
d0 b0,0 b1,0 b2,0 b3,0 b4,0 . . .
QR Code JIS X 0510 Encoder In VS .NET
Using Barcode maker for .NET Control to generate, create QR Code ISO/IEC18004 image in Visual Studio .NET applications.
d1 b0,1 b1,1 b2,1 b3,1 b4,1 . . .
QR Code Scanner In .NET Framework
Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET framework applications.
d2 b0,2 b1,2 b2,2 b3,2 b4,2 . . .
Generate Bar Code In .NET Framework
Using Barcode creation for VS .NET Control to generate, create barcode image in .NET applications.
d3 b0,3 b1,3 b2,3 b3,3 b4,3 . . .
Recognizing Bar Code In VS .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
d4 b0,P b1,P b2,P b3,P b4,P . . . b0,P = b0,0 b0,1 b0,2 b0,3 b1,P = b1,0 b1,1 b1,2 b1,3 b2,P = b2,0 b2,1 b2,2 b2,3 b3,P = b3,0 b3,1 b3,2 b3,3 b4,P = b4,0 b4,1 b4,2 b4,3
Quick Response Code Maker In C#
Using Barcode maker for .NET framework Control to generate, create QR-Code image in .NET framework applications.
Block size = Q bytes
Encode QR Code 2d Barcode In Visual Studio .NET
Using Barcode drawer for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
bx,y : Data block y of parity group x bx,P : Parity block of parity group x
QR Code 2d Barcode Generator In Visual Basic .NET
Using Barcode encoder for .NET Control to generate, create QR Code ISO/IEC18004 image in .NET framework applications.
Figure 5.1 Storage organization under RAID-3 striping scheme
Bar Code Generation In .NET Framework
Using Barcode generation for Visual Studio .NET Control to generate, create bar code image in .NET framework applications.
b2,0 b2,1 b2,2 b2,3 b2,P
Print Barcode In .NET
Using Barcode creator for .NET Control to generate, create bar code image in Visual Studio .NET applications.
Figure 5.2 Reconstructing media data with erasure correction
Bar Code Generator In .NET
Using Barcode maker for Visual Studio .NET Control to generate, create barcode image in .NET applications.
b2,0 Any 4 blocks Erasure Correction b2,1 b2,2 b2,3
USPS Confirm Service Barcode Maker In Visual Studio .NET
Using Barcode creation for Visual Studio .NET Control to generate, create USPS PLANET Barcode image in Visual Studio .NET applications.
The parity block is computed from the (N D 1) data blocks using exclusive-or computation. The storage is then allocated in whole parity groups instead of individual blocks to ensure that data blocks within a parity group always store data from the same media stream. This RAID-3 striping scheme enables the system to mask the failure of any one of the N D disks to continue operating through erasure correction processing (Figure 5.2). Retrievals and transmissions are organized into rounds as shown in Figure 5.3. We assume that all media streams are encoded with constant-bit-rate encoding at the same bit-rate. Shortterm bit-rate variations (e.g., due to I, P, B frame differences in MPEG) are assumed to be absorbed by client buffers and hence the disk can simply retrieve exactly one media block from each of the N D disks for each active media stream in each round. Note that this can also be extended to support other bit-rates which are multiples of a base rate. These higherrate streams can be treated as multiple base-rate streams and hence we will ignore this minor complication in the rest of the chapter. With the previous disk scheduler, a complete parity group, including the (N D 1) media blocks and the associated parity block are all retrieved for each stream in a service round. This
EAN-13 Supplement 5 Recognizer In VS .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
Reliable and Fault-Tolerant Storage Systems
Draw EAN 13 In VB.NET
Using Barcode creation for .NET Control to generate, create European Article Number 13 image in Visual Studio .NET applications.
Figure 5.3 Retrieval and transmission scheduling algorithm
Recognizing Barcode In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
enables the server to sustain non-stop service even when one of the disks fails by computing the unavailable media block using erasure-correction computation over the remaining blocks in the parity group. Let Rv be the media bit-rate. Then the retrieved (N D 1) media blocks will be transmitted in the next service round and the service round length is thus given by Tr = (N D 1)Q Rv (5.1)
Encoding Barcode In Visual Studio .NET
Using Barcode drawer for ASP.NET Control to generate, create barcode image in ASP.NET applications.
Under this scheduling algorithm, the total number of buffers required is given by B p = KN D Q + K (N D 1)Q (5.2)
Barcode Encoder In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create bar code image in ASP.NET applications.
where the rst term is the buffer requirement for retrieval, the second term is the buffer requirement for transmission, and K is the maximum number of requests that can be served in a service round (see Section 5.3.4). Transmission requires fewer buffers because the retrieved parity block is not transmitted and hence the buffer can be reused. For a server with a large number of disks, the single parity disk may not provide suf cient redundancy to maintain acceptable reliability. This problem can be solved by dividing the disks into clusters where each cluster has its own parity disk (e.g., Streaming RAID [1]). Multiple disk failures can be sustained as long as no more than one disk fails in a cluster. Results
Universal Product Code Version A Drawer In Java
Using Barcode generator for Java Control to generate, create UPC-A Supplement 2 image in Java applications.
Scalable Continuous Media Streaming Systems
Code 128 Code Set B Printer In Visual Basic .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create Code 128A image in Visual Studio .NET applications.
discussed in this chapter can be directly extended to these clustered schemes and hence we will focus on single-cluster disk arrays in the rest of the chapter.
Barcode Generator In Visual Basic .NET
Using Barcode encoder for VS .NET Control to generate, create barcode image in Visual Studio .NET applications.
5.3.3 Disk Performance Model
To model the disk, we extend the disk model introduced in 3 by incorporating additional details such as head-switching time and retrieval across track boundary. Let Ntrk be the number of tracks per recording surface (or number of cylinders), Nsuf be the number recording surfaces, W be the disk rotation speed in rounds per second, S be the sector size in bytes, Nzone be the number of zones, Yi (i = 1, 2, . . . , Nzone ) be the number of sectors per track in zone i. Note the disk transfer rate, denoted by X i (i = 1, 2, . . . , Nzone ), is also zone dependent and is given by X i = SYi W To simplify notations in later sections, we de ne X min = min {X i |i = 1, 2, . . . , Nzone } Ymin = min {Yi |i = 1, 2, . . . , Nzone } Ymax = max {Yi |i = 1, 2, . . . , Nzone } (5.4) (5.5) (5.6) (5.3)
and we shall leave out the subscript i in X i and Yi when representing random variables (i.e., X , Y ) instead of system parameters. To model disk performance, we rst consider the time it takes to serve a request. Speci cally, disk time for retrieving a single request can be broken down into four components, namely, xed overhead (e.g., head-switching time, settling time, etc.) denoted by , seek time denoted by tseek , rotational latency denoted by trot , and transfer time denoted by txfr : treq = + tseek + trot + txfr (5.7)
Seek time depends on the seek distance and can be modeled by a seek function f seek (n) where n is the number of tracks to seek. For rotational latency, the random variable trot will be uniformly distributed between 0 and W 1 . Finally, the transfer time txfr comprises three components: txfr = Q + thsw + ttrack X (5.8)
where the rst term is the time it takes to read the media block of Q bytes from the disk surface; the second term is the total head-switching time incurred if the media block spans more than one track in the cylinder; the last term is the total track-to-track seek time incurred if the media block spans more than one consecutive cylinder. Take the Quantum Atlas-10K disk model as an example, transfer time for retrieving a 64KB media block ranges from 4.59ms to 6.69ms depending on the zone, head-switching time is 0.176ms, and track-to-track seek time is 1.25ms. Therefore, unless one sacri ces some storage (7 10% depending on zone) to prevent a media block spanning two tracks, the effect of trackcrossing should not be ignored.