How To Build A Portable Usb Hard Drive
- Thread starter yogi
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Sorry, i meant myself. Edited. 
QUOTE(waterloo_sunset @ May 17 2006, 04:29 PM) [snapback]51561[/snapback]
There are some known issues with usb 2.0 external drives even with WinXP with ppl getting delayed write errors and what not. And nobody has been able to pinpoint the exact cause yet. Hit and trial is the only alternative
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For those that don't know what a delayed write failure is :
All modern operating systems cache data writes to improve performance. Hard drives are extremely slow, when compared to RAM access (which is slow when compared to L2 Cache, and so on right to the CPU's registers). The OS assumes that most of the time when you use data on the drive and save it, there's a fair possibility that you might save that data again some time soon (or a nearby, similar piece). It saves time to just store that data in RAM for a few moments (and act like it saved it to disk to you and the rest of the programs running) and "save up" until you have a big enough batch of data to write all at once. Also, if you re-change that data (ever click save two or three times in a row on a Word document?), it doesn't waste time writing out to the slow disk the first time(s) by using the exponentially faster ram. This is called a delayed write. The OS is holding, or caching, that data until it's good and ready to write it (which usually happens within a few seconds).
A delayed write failure is when later comes, and the system tries to write the data out to the disk, and something doesn't work, so the data gets lost (or partially lost or maybe it got there but didn't confirm that it did, the OS doesn't know). This isn't good, because the data lost could be only part of a file, or there could be random data overwritten in the middle of other files (if a file only got 1/2 moved). Either way, bad news. The write shouldn't have failed unless you disconnected the drive or shut down the computer -- which is why you shouldn't unplug external drives without "disconnecting" them in the OS first and is why you should always "shut down" Windows properly and not just yank the plug.
Assuming you weren't doing those things... This can also be a very bad sign for the drive's health physically (or the drive's cable). Obviously, if it randomly can't write data, something is wrong. I would probably take immediate action to backup any data on the drive. Remember, its never a question of "if" a drive will die, its a question of when. We haven't yet figured out how to build a machine that spins at 7200 RPM 24 hours a day, 7 days a week, and have it last forever -- not if we plan to sell it on Newegg.com for 50 cents a GB anyway. Eventually, on the 20 billionth spin round, something in that mechanism is going to break or wear down.
Pinched from here
There are some known issues with usb 2.0 external drives even with WinXP with ppl getting delayed write errors and what not. And nobody has been able to pinpoint the exact cause yet. Hit and trial is the only alternative
[/b]
For those that don't know what a delayed write failure is :
All modern operating systems cache data writes to improve performance. Hard drives are extremely slow, when compared to RAM access (which is slow when compared to L2 Cache, and so on right to the CPU's registers). The OS assumes that most of the time when you use data on the drive and save it, there's a fair possibility that you might save that data again some time soon (or a nearby, similar piece). It saves time to just store that data in RAM for a few moments (and act like it saved it to disk to you and the rest of the programs running) and "save up" until you have a big enough batch of data to write all at once. Also, if you re-change that data (ever click save two or three times in a row on a Word document?), it doesn't waste time writing out to the slow disk the first time(s) by using the exponentially faster ram. This is called a delayed write. The OS is holding, or caching, that data until it's good and ready to write it (which usually happens within a few seconds).
A delayed write failure is when later comes, and the system tries to write the data out to the disk, and something doesn't work, so the data gets lost (or partially lost or maybe it got there but didn't confirm that it did, the OS doesn't know). This isn't good, because the data lost could be only part of a file, or there could be random data overwritten in the middle of other files (if a file only got 1/2 moved). Either way, bad news. The write shouldn't have failed unless you disconnected the drive or shut down the computer -- which is why you shouldn't unplug external drives without "disconnecting" them in the OS first and is why you should always "shut down" Windows properly and not just yank the plug.
Assuming you weren't doing those things... This can also be a very bad sign for the drive's health physically (or the drive's cable). Obviously, if it randomly can't write data, something is wrong. I would probably take immediate action to backup any data on the drive. Remember, its never a question of "if" a drive will die, its a question of when. We haven't yet figured out how to build a machine that spins at 7200 RPM 24 hours a day, 7 days a week, and have it last forever -- not if we plan to sell it on Newegg.com for 50 cents a GB anyway. Eventually, on the 20 billionth spin round, something in that mechanism is going to break or wear down.
Pinched from here
popcorn
Senior Member
best option to back up is on dvd rw. just buy 10 dvd-rw and have 2 sets of backups. Assuming your data is fitting in 5 dvds.never relay on usb drives or created usb harddisk. its(usb hardisk-converted) not reliable and it has lots of compatibility and other hardware/heating/voltage etc problems.yogi....there is a possibility of fat32 to ntfs transfers errors.files over 4GB(single file) from fat32 to ntfs will corrupt files while transfering.(or vice-versa)
@sifyfanI have never used ntfs, and I never will use it. FAT32 is sufficient for my needs. And yes, I would never rely on any hardisk, whether it be internal or external or flash drive. @blr_pgood explanation...but its logical...I guess logical for software people hehehe 
Also I did not have to go for a replacement, it works fine. You wrote about backing up to a drive under warranty...but what if that drive fails anyway and the company cannot recover your data 
Also I did not have to go for a replacement, it works fine. You wrote about backing up to a drive under warranty...but what if that drive fails anyway and the company cannot recover your data QUOTE(sifyfan @ May 18 2006, 11:25 AM) [snapback]51630[/snapback]
best option to back up is on dvd rw. just buy 10 dvd-rw and have 2 sets of backups. Assuming your data is fitting in 5 dvds.
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Err..no dvd-rw or any rw media for that matter is *NOT* suitable for backup, just temp backup if that.
If you choose to use dvd to backup, dvd-r(+r) is much better.
QUOTE(yogi @ May 19 2006, 09:19 AM) [snapback]51688[/snapback]
You wrote about backing up to a drive under warranty...but what if that drive fails anyway and the company cannot recover your data
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recover your data !!! :blink: they won't recover your data, they will only give you a replacement drive. How long they take to get back to you can be anywhere from a week to a month.
If you want to recover your data from a failed drive, depending on how bad the problem is you could end up paying 10xthe cost of the HD to a company that specialises in this. That is if other methods at your disposal don't work. Always cheaper to backup on to redundant drives that is if your data is worth anything to you at all.
When i said backup to another HD, this HD remains in a drawer, only brought out once a month for the backup. Chances of it failing are lower than if its in your computer. In case of a failure you wait for warrantied drive to arrive and then sync to that from the backup. You can also backup to dvd-r's as well for triple redundancy. Since you have < 100GB thats 2.5 spindles of 10-pack dvd-rs. Make sure you get a dvd good writer in that case.
best option to back up is on dvd rw. just buy 10 dvd-rw and have 2 sets of backups. Assuming your data is fitting in 5 dvds.
[/b]
Err..no dvd-rw or any rw media for that matter is *NOT* suitable for backup, just temp backup if that.
If you choose to use dvd to backup, dvd-r(+r) is much better.
QUOTE(yogi @ May 19 2006, 09:19 AM) [snapback]51688[/snapback]
You wrote about backing up to a drive under warranty...but what if that drive fails anyway and the company cannot recover your data
[/b]
recover your data !!! :blink: they won't recover your data, they will only give you a replacement drive. How long they take to get back to you can be anywhere from a week to a month.
If you want to recover your data from a failed drive, depending on how bad the problem is you could end up paying 10xthe cost of the HD to a company that specialises in this. That is if other methods at your disposal don't work. Always cheaper to backup on to redundant drives that is if your data is worth anything to you at all.
When i said backup to another HD, this HD remains in a drawer, only brought out once a month for the backup. Chances of it failing are lower than if its in your computer. In case of a failure you wait for warrantied drive to arrive and then sync to that from the backup. You can also backup to dvd-r's as well for triple redundancy. Since you have < 100GB thats 2.5 spindles of 10-pack dvd-rs. Make sure you get a dvd good writer in that case.
besides the convenience of a smaller amount of physical storage space, I dont see any difference between burning on a dvd or a cd. So dvd writer is how much?And anyway how much does a blank dvd cost?? 40 or 50?? I can store one dvd's data on 6 cd's ...cost=9*6= Rs 54.
So, I have zero info about dvd...please answer these questions...1. What is the storage life for a dvd-r ? (for a Sony 700 mb cd its 3-5 yrs)2. Should I buy external usb dvd writer or buy one that replaces the cd burner? If I replace the cd burner...then I cant read/write cd's anymore? Or I have to go for a combo solution?3. Also which brand and model shoud I go for ?4. I dont want to burn a dual layer dvd...single layer is fine..., and Sushubh said, an empty dvd-r costs just 20 bucks?? Which brand is the best brand for dvd-r?? - is it sony ???5. Which is better? dvd-r or dvd+r