Solved

Scheduling algorithm for disk

Posted on 1998-10-08
2
270 Views
Last Modified: 2010-04-27
As disk technology improves, the seek time is becoming progressively shorter, and it may soon take less time to seek to the desired cylinder than it takes for the desired sector to rotate under the disk heads.
Under this circumstances, would it make sense to use any of the scheduling algorithm such as First come first serve to order requests for the same track. If so which algorithm is the best
0
Comment
Question by:Novice100898
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 12

Accepted Solution

by:
mark2150 earned 70 total points
ID: 1011271
Your circumstance can't happen. You can't determine what sector is flying by until *after* you've seeked and settled to desired cylinder. No matter how fast cylinder seek time is, your access time will always be this time *plus* a 1/2 rotation (on average)

Taccess.avg = Tseek + Trot / 2

Since majority of reads are sequential and RAM is cheap, cylinder buffering reduces "2nd read" latency by substantial margin. Controller reads entire track/cylnder in one gulp and heads can start seek of next cylnder while buffered data transfers out.

M
0
 

Author Comment

by:Novice100898
ID: 1011272
If the seek time become negigible and there is no caching in place, can we have an algorithm which will help to speed up the rate at which data is access. That is if the first request is at sector 3 track 2 and second request at sector 6 track 2 and third request at sector 8 track 2 and they are all in a queue, will it be possible to implement any algorithms to solve the problem.
0

Featured Post

Simplifying Server Workload Migrations

This use case outlines the migration challenges that organizations face and how the Acronis AnyData Engine supports physical-to-physical (P2P), physical-to-virtual (P2V), virtual to physical (V2P), and cross-virtual (V2V) migration scenarios to address these challenges.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

this article is a guided solution for most of the common server issues in server hardware tasks we are facing in our routine job works. the topics in the following article covered are, 1) dell hardware raidlevel (Perc) 2) adding HDD 3) how t…
This paper addresses the security of Sennheiser DECT Contact Center and Office (CC&O) headsets. It describes the DECT security chain comprised of “Pairing”, “Per Call Authentication” and “Encryption”, which are all part of the standard DECT protocol.
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…
Suggested Courses

734 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question