The ability to continue non-stop when a hardware failure occurs. A fault-tolerant system is designed from the ground up for reliability by building multiples of all critical components, such as CPUs, memories, disks and power supplies into the same computer. In the event one component fails, another takes over without skipping a beat.
Tandem and Stratus were the first two manufacturers that were dedicated to building fault-tolerant computer systems for the transaction processing (OLTP) market.
High Availability
Many systems are designed to recover from a failure by detecting the failed component and switching to another computer system. These systems, although sometimes called fault tolerant, are more widely known as "high availability" systems, requiring that the software resubmits the job when the second system is available.
Redundant Hardware
True fault tolerant systems with redundant hardware are the most costly because the additional components add to the overall system cost. However, fault tolerant systems provide the same processing capacity after a failure as before, whereas high availability systems often provide reduced capacity. See fault management.
A RAID Array
This RAID II prototype in 1992, which embodies principles of high performance and fault tolerance, was designed and built by University of Berkeley graduate students. Housing 36 320MB disk drives, its total storage was less than the disk drive in the cheapest PC only six years later. (Image courtesy of The Computer History Museum, www.computerhistory.org) See RAID.
Redundancy
Redundancy is the hallmark of fault tolerant systems. This storage server from Xtore Extreme Storage (www.xtore-es.com) contains multiple, hot-swappable power supplies to ensure continued operation.
Tandem and Stratus were the first two manufacturers that were dedicated to building fault-tolerant computer systems for the transaction processing (OLTP) market.
High Availability
Many systems are designed to recover from a failure by detecting the failed component and switching to another computer system. These systems, although sometimes called fault tolerant, are more widely known as "high availability" systems, requiring that the software resubmits the job when the second system is available.
Redundant Hardware
True fault tolerant systems with redundant hardware are the most costly because the additional components add to the overall system cost. However, fault tolerant systems provide the same processing capacity after a failure as before, whereas high availability systems often provide reduced capacity. See fault management.
A RAID Array
This RAID II prototype in 1992, which embodies principles of high performance and fault tolerance, was designed and built by University of Berkeley graduate students. Housing 36 320MB disk drives, its total storage was less than the disk drive in the cheapest PC only six years later. (Image courtesy of The Computer History Museum, www.computerhistory.org) See RAID.
Redundancy
Redundancy is the hallmark of fault tolerant systems. This storage server from Xtore Extreme Storage (www.xtore-es.com) contains multiple, hot-swappable power supplies to ensure continued operation.
 | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2008 The Computer Language Company Inc. All rights reserved. |
Additional Resources
- IE8's "best" feature broken: stick with Firefox
- IE8's "best" feature broken: stick with FirefoxIE8 BetaIE8 is in Beta, it is not the finished product. There will be issues adn problems. I am currently using it as well, and the problems I do have, I have let Microsoft know. It is a work in progress.That's...
- Discussion threads 2008-09-04
- DoS vulnerability hits Google's Chrome, crashes with all tabs
- DoS vulnerability hits Google's Chrome, crashes with all tabsChrome will have security problems, and they will NOT all of a sudden gainshare. That said, the Google brand is very powerful, and people use it every day to search, and there will be lest resistance to trying Chrome than there was...
- Discussion threads 2008-09-03
- Dell repair adventure, day 4
- Dell repair adventure, day 4Litigation"The expectation is that a person will arrive on site the next day having 1) the skills to diagnose and repair the problem, 2) the parts necessary to repair problem and 3) the tools necessary to do the work."1. Litigate: misleading advertising.2. Where is ZDNET's legal...
- Discussion threads 2008-09-03
- Citrix Business Solutions: Powered by Datacore Software
- DataCore Software provides storage virtualisation solutions that make storage and SAN infrastructures efficient, fault tolerant, flexible and virtual. DataCore Storage Virtualisation is the foundation for the Total Enterprise Virtualisation - the combination of proven virtualisation solutions into comprehensive, enterprise-wide, virtual infrastructures, comprising desktops, servers and storage. ...
- White papers 2008-09-03
- Acer Aspire X1200-U1520A
- The Acer Aspire X1200 line of minidesktops fits budget PC components inside a compact case and offers some features that let it act as a light home theater companion. Our $450 review model came with a dual-core AMD processor, 4GB of memory, and 64-bit Windows Vista, which make it...
- Product reviews 2008-09-02
- First look at Google Chrome
- First look at Google ChromeDownloaded and took a look at chromeAnd was immediately struck by just how much annoying advertising crap ZDNet puts on their site.Inadvertently? I vote on purpose.Inadvertently? I vote on purpose. I'd believe "inadvertently" if Chrome were released a month later - but a [b]day[/b] later? No,...
- Discussion threads 2008-09-02
- Google Chrome bats 1-for-3 for me
- Google Chrome bats 1-for-3 for meNo AdBlock Plus...no Chrome. Simple as that.what do you expect it's a beta!'Ordinary' users would never be trying to surf with a beta release of a niche browser minutes after it's release.Don't be such an arse - you know damn well that most browsers...
- Discussion threads 2008-09-02
- Are we to have two Internets?
- Are we to have two Internets?And what machine were you testing?"Apache dies when hit with about seven to ten thousand user floods. Yaws just kept on going on up to 85,000 simultaneous users."What kind of setup did you test this on?Great responseI don't agree with all your premises but I...
- Discussion threads 2008-09-01
- Question about Gov. Sarah Palin
- Question about Gov. Sarah PalinI searched online and got on the site with this linkhttp://www.state.ak.us/but could not get to anywhere when I clicked on her image to go to that page, eitherBlame ObamaObama's campaign team, probably caught by surprise at this announcement, are probably trying to dig up whatever dirt...
- Discussion threads 2008-08-29
- Psystar files answer to Apple complaint
- Psystar files answer to Apple complaintBut they don'tYou have to modify Leopard to get it to run on non-Apple hardware.Case closed, Psystar loses.Especially the asinine argument that OS X is not a copyrightable work.Except....I would imagine Psystar is well backed in its endeavor. Or would be. There is...
- Discussion threads 2008-08-29
- Square Document Management System (zip)
- SQUARE is a Document Management & Collaboration System on Lotus Domino. It is a freeware and support open source in several application extension AXION. It is designed for managing various documents such as e-mail, electronic document, mail, paper document. It brings the users the smoothest experience in searching, sharing, editing,...
- Software downloads 2008-08-29
- Peek
- Here's the Peek pitch: there are those of us who are dependent on e-mail, but don't want to get a smartphone--maybe because of pricing, or because smartphones can be pretty complicated for first-time users. So forget the BlackBerry, the Treo, and the iPhone; the people behind Peek wanted to introduce...
- Product reviews 2008-08-28
- Internet Explorer 8 Beta 2 vs. Firefox 3.0.1
- Internet Explorer 8 Beta 2 vs. Firefox 3.0.1All part of the MS plan to keep browsers dumbded down. If we had reallygood browsers, how would they get people to use MS proprietary solutions for rich internet applications.RE: Internet Explorer 8 Beta 2 vs. Firefox 3.0.1The title says Firefox 3.0.1The graph...
- Discussion threads 2008-08-27
- "Why do you hate Vista so much?"
- "Why do you hate Vista so much?"Reasons that Vista bothers me...1) I have now spent over 4 hours trying to get SP1 installed on a new box.... the BSOD's are blurry (kind of funny huh?) The same box, XP installed with less heart ache and fewer issues... while I am...
- Discussion threads 2008-08-27
- IE 8 Beta 2 ready for download
- IE 8 Beta 2 ready for downloadRE: IE 8 Beta 2 ready for downloadIt's been a pleasure to work with the IE team to deliver some of the first Visual Search services out there. They're a cool team - and deserve some kudos. We're all looking forward to some user...
- Discussion threads 2008-08-27
- Major security hole found in iPhone
- Major security hole found in iPhonewhose fault?Seems to me you're blaming Apple for bad coverage when you should be blaming O2. Didn't they give you some sort of trial period when you sign up to see how the coverage was in your area?The risk Me-Firsters takeEr, I mean early...
- Discussion threads 2008-08-27
- Apple iPhone ad banned
- Apple iPhone ad bannedBetter than the alternativesMy iPhone works as promised.My Macs are more reliable than my Windows boxes.In short, there are better options.Why anyone would buy anything from Apple...is beyond me. Especially the iPhone. It doesn't work as promised in sooooo many ways.i guess every iphone user is mad...
- Discussion threads 2008-08-27
- Class action suit filed over Apple's 3G speed claims
- Class action suit filed over Apple's 3G speed claimsWhen will they learn?I blame the bozos that buy Apple products. Proprietary, over-hyped, over-priced, mediocre but beautifully designed products that are marketed in very creative ways. There is a sucker born every minute. Just ask all the 3G iPhone...
- Discussion threads 2008-08-21
- Seinfeld to host the Microsoft Makeover
- Seinfeld to host the Microsoft MakeoverRE: Seinfeld to host the Microsoft MakeoverPersonally, never liked the comedy styling of Jerry Seinfeld. I'm not partial to the whining and other obvious childish renderings.But how apropos for Microsoft!!!!!!Annnnnnnd cue the ABMers.ACTION!!!!A PC perspective was done about a year ago"Do you need a lift...
- Discussion threads 2008-08-21
- Microsoft SideWinder X5 Mouse
- Microsoft's new SideWinder X5 Mouse is a stripped-down version of last year's Editors' Choice-winning SideWinder Gaming Mouse. Where the original model was a packed-to-the-gills gaming powerhouse, the X5 feels flimsy and expensive for the $60 Microsoft wants you to spend. We're willing to accept a more basic version of a...
- Product reviews 2008-08-20
Neighboring Terms
Premier Vendor Content Whitepapers, webcasts & resources from our Power Center Sponsors
Ultraportables
- Understanding Ultraportable Laptops (BNET)
- Five steps to protect mobile devices anywhere, anytime (TechRepublic)
- View all ZDNet Toshiba laptop reviews
- From our sponsors
- Toshiba Satellite® U400 Series
-
- The ultra-portable, ultra-stylish Satellite® U405 is a smart choice for you and your small business. Only from the laptop expert, Toshiba. Explore the complete laptop lineup »
-
