Hard DrivesI have had enough hard drives that I can make some sense about their reliability. I have had a variety of SCSI drives, starting with 2gb 10mb/sec SCSI. Most are not currently in use.
I have had a variety of IDE drives. I have seen a few serious failures of drives that I have inherited. For all drives I have purchased, when there were problems, I could always copy most or all the files before the drive failed.
I have had several SATA drives so far.
I usually run my main computer 24x7. It is very well cooled. See Keeping Everything cool for details. |
I bought 2 used supermicro sata racks. These hold 5 sata drives in three 5.25 inch drive bays. There is a 92mm fan in the rear that cools the hard drives. This fan is about 32mm thick, rated at 0.31 amps, 2900 rpm, and 55.1 cfm. As expected, it moves lots of air and keeps the hard drives cool. What is interesting, is my 4 drive scsi rack uses 3 tiny 40mm*10mm fans, with a total of about 15 cfm, and it can keep 15,000 rpm scsi drives cool. I decided to install an inline fan speed controller in order to keep the fan noise down.
The instructions that come with the rack are decent, but leave much room for the imagination. The rack comes with 13 flat head screws, 24 round head screws, and 7 round head screws with lock washers. Now what are they all for? The hard drive rack looks like it should be using flat head screws, but with 4 screws per drive, and 5 drives, that should be 20 screws, but only 13 are provided. Clearly, some screws are for securing the rack in the computer. I would guess they are the ones with lock washers, but I would assume an even number, with the same on either side of the rack. If anyone knows the answer, please let me know.
If you don't use low profile screws on the drive trays, the drive rack is hard to insert. Don't force it, get low profile screws. The rack doesn't have any provision to stagger the spin up of the drives, unlike my scsi drive rack. I called Supermicro, and they said their controller does it automatically. I guess if you don't have their controller, you are out of luck. It does have a fan rpm alarm and a temperature alarm which can be configured via jumpers on the back of the rack.
If you don't need hot swap, and you are happy with 4 drives per 3 5.25 inch drive bays, use a coolermaster 4-in-3 module. It has a nice, big, quiet 120mm fan that does a great job of keeping the drives cool, and is much cheaper. If you get tired of opening the case and disconnecting all the drives data and power cables, this is a great product except for the noisy fan.
I have always had scsi hard drives. I now use them for my operating system, not for general storage. They are typically smaller than IDE or SATA drives, but that isn't a problem as the OS doesn't need much space. If you want 10,000 rpm, scsi used to be the only way to go, until Western Digital introduced the raptor drive. If you want 15,000 rpm, scsi is still the only way to go. (The higher rpm's allow faster file access time, as the platter rotates faster). New things like command queuing for SATA has been around for many years in the scsi world.
SCSI also has had the ability to hot-swap, that is remove and insert while the computer is running, which is a new thing for SATA. The hot swap scsi drives have 80 pin connectors on the back of the hard drive. The 80 pins supply data (which is either 50 or 68 pins for scsi), power, scsi id, some led signals and the like. You can buy hard drive bays which hold multiple hard drives and allow them to be inserted or removed via hard drive trays which bolt to the hard drive. This way, you don't have to open the computer case to switch hard drives.
This has always sounded like a great idea to me, however they have some drawbacks. The first is they are generally expensive. The second is some do not allow enough air flow over the hard drives to keep them cool enough. A 15,000 rpm scsi hard drive can easily draw 20 watts. I found a decent 4 hard drive bay scsi hot swap rack made by Chieftec. It has may good features. Like any serious hard drive rack, you can delay the power up of the hard drives. Since they need peak power during spin up, when you turn your computer on, all the drives will start to spin up. This allows a delay before the drives in the rack spin up. (Some cheap SATA racks lack this feature). There are lights for each drive to indicate power and access. There is good airflow provided by 3 40mm exhaust fans. There is an alarm that sounds if the rack gets too hot or any fan fails. As for the bad, the front of the hard drive tray is plastic along with the lock that secures the tray. I did manage to break (and repair) one tray lock. There is no documentation online for this product, as it has been unavailable for several years.
Recently, the alarm has been sounding. You can reset it with a button, but it kept on sounding. I opened the case, and observed one of the fans was barely rotating. I looked up the fan specs and found it was a simple sleeve bearing fan with a rated life of 30k hours. I also looked at my hard drive temperature, and found though I only had 2 hard drives powered up, one was around 48C, which I don't like, especially since it was just idling. I switched the bottom fan (failed) with the top fan, and the temperature dropped to 44C which was better but not good. I ordered 3 fancy fans which had a bit more airflow, a superior bearing with 100k hour rated life, and were even quieter than the original fans. As soon as hey arrived, I swapped in the new fans for the old fans. Now all my hard drives are cool, and the alarm doesn't sound. The previously hot drive is now at 40C.
This is a solid state drive. What that really means is it is a flash drive. How does that differ from a thumb drive? Well, a thumb drive is optimized for low cost and a SSD is optimized for speed. There are 8 flash chips inside the OCZ Core SSD and there is a controller chip that implements 'wear levelling', which tries to keep the number of writes to each memory cell roughly level. If one used the FAT file system, it has a File Allocation Table that gets updated whenever a file on the system gets updated. So the FAT table will see many more writes than the rest of the disk. Modern file systems are more sophisticated than FAT, but the same principle applies.
A solid state disk having no moving parts will tend to be more reliable than a conventional disk with moving parts. Also a conventional disk has what is known as 'seek time' which is the time it takes for the disk head to move from one track to another. A SSD doesn't have a head, so no seek time. A conventional disk has a latency time which is the time it takes for the disk to rotate under the head. A SSD has no disk, and so no latency time. Most SSD's use much less power than conventional disk drives. The OCZ Core uses a maximum of 1.8 watts. In case you go to high altitudes with hard drives, SSD's are unaffected by altitude unlike conventional disks drives. SSD's come in two flavors, SLC (single level cell) which is expensive, fast, and very durable, and MLC (multi level cell) which is less expensive, slower, and about 10 times less durable. With MLC you can store multiple values in a cell, typically 2 bits, which is twice the density of SLC. The OCZ Core is a MLC drive.
Last Thanksgiving I was able to get a SSD for a reasonable price of $77 after rebate. I am using it for the operation system partitions on my computer. It is a good idea to minimize writing small files to the SSD, as the SSD writes a minimum of 128kb internally whenever you do a write. On linux, simply mount the partition with the noatime switch. On windows, there are a variety of tricks to minimize disk writes. There are good guides on the OCZ web pages for a variety of things that can be done to minimize writes. Here is what I have done. 1) Move the page file to a different disk. 2) Move 'documents and settings' to a different disk. 3) A few registry tweaks. 4) Enable write caching on the SSD. 5) Configure dskcache +p. 6) Disable the indexing service. With these tweaks, my writes are about 15% of my reads of the disk. Since booting today, my reads are 2.34gb and my writes are 228mb (using hddled, a great tool).
I used to use 15k rpm scsi drives for my OS. They were reasonably cheap, but they made a bunch of noise, and used a lot of power. I have removed my hot-swap scsi enclosure, scsi disks and scsi card, and replaced it with the OCZ SSD. Faster, less power, less noise, more reliable. On my computer, the read speed measured at 118 mbytes/second and the write speed measured at 80 mbytes/second, using atto disk benchmark and a sata I controller.
I have a Sony 4mm DAT drive. There is now a newer one, the SDT-9000, which is faster and has a higher capacity (what else is new?). It is reasonably reliable. I have had to send it back once, since it broke in a way that I don't recall.
Well it broke again 12/27/97. Did a full backup flawlessly, but refused to eject the tape. The manual eject button does no good, and when I send a SCSI command to eject, I get an error return. I am most unimpressed. I have probably made 20-30 tapes, and it has failed twice. I will send it back to Sony, and no doubt pay plenty. This drive is still listed on their web page, and people are still selling it, so I would guess it is still being made. Hope Sony can get my backup tape out... I now do not recommend this drive at all under any circumstances due to poor reliability.
Well it broke again Dec-24-1999. Backed up some data, then got a buncha errors, timeouts, and the like. And it was with new tape. So I traded it in with New Image International. They told me that the Sony sdt-7000, sdt-9000, and sdt-10000 have 'soft' heads, and when they go, the cost to fix the heads is about what the drive is worth. They said the HP DAT-8 was better, so I got it. I will eventually get a DLT drive, when they get cheaper and I get more money.
I have a Dazzle Universal 6 in 1 Reader. (Dazzle has since been acquired by Pinnacle). This is designed to read and write CompactFlash, IBM Microdrive, SmartMedia Card, MultiMedia Card/Secure Digital, and Memory Stick media. Sounds good, right? It actually works ok on Windows XP. On Windows 2000, when you install it, you hose up the operating system in a really major way. After much thrashing I was able to fix Windows the first two times I installed the operating system. The third time I installed Windows and the reader, I was unable to fix the OS. I spent many hours of hair pulling and swearing to no avail. I searched the dazzle web site for into to help, to no avail. I sent their tech support email, and I finally received a reply 8 days later (after making them weasel of the month). I have since upgraded to Windows XP, in order to have a working computer.
So in my experience, the best way to completely and irrevocable screw up Windows 2000, is to install a Dazzle reader. I have overcome many hardware and software problems in the past, but this is the worst by far. I cannot overemphasize the poor quality of the Dazzle software. I am used to software not working, or crashing, but breaking the operating system in a fatal way requires extra effort, and Dazzle has done it.
Here are my replies to their email. Their text in in italics. My editorializing is in [square brackets]:
To: smmicro4@custhelp.com
Subject: Re: Windows 2000 professional [Incident:
030218-000454]
Recently you requested personal assistance from our on-line
support center. Below is a summary of your request and our
response.
We will assume your issue has been resolved if we do not hear
from you within 168 hours.
Thank you for allowing us to be of service to you.
You may also update this question by replying to this message.
Because your reply will be automatically processed, you MUST
enter your reply in the space below. Text entered into any other
part of this message will be discarded.
[===> Please enter your reply below this line <===]
Well, I don't have a USB card to add or remove. It is built
into my motherboard. Therefore, 2a, 2b, 2c, 2d, 2e, 2f are
useless.
I do have antivirus software running, Norton antivirus. I do have
another Windows 2000 pro system correctly running on my machine.
Since I cannot be without my OS for a week, I did a fresh OS
install and used Windows XP pro. Since I didn't find anything on
your FAQ (and I still can't find any entries with the word virus
in them), and since it took you a week to reply to me, and since
your product has always rendered windows 2000 useless, and since
you didn't send email to my hotmail account as I asked (since I
can't read email when my system is hosed), I have decided to make
dazzle weasel of the month at weasel.com. See www.weasel.com for
details.
So in that sense my problem is resolved. However your problem
sure isn't resolved.
Have a nice day,
Turbo,
domain owner of weasel.com
PS: I really like the quote "I'm sure your questions are
answered"
[===> Please enter your reply above this line
<===]
If your issue remains unresolved, please update this question
here.
Subject Windows 2000 professional
Discussion Thread
Response (Naveen)02/27/2003 05:09 AM
Dear Turbo,
Thanks for your patience and your confidence in Dazzle.We are
very sorry for this delayed feed back.We will make sure to give
them in due time.
[I suspect that they replied at all because I made
them weasel of the month, and sent their PR person an email about
that. Can't prove it. I also like the sorry for the delayed feed
back message. All of their email seems to have it as boiler-plate
and for good reason.]
There could be numerous other reasons for the system
reboot.
[The reason for the system reboot is that I rebooted
the system. The problem is that the system won't finish booting
up, not the 'system reboot'.]
Please go through the following and let us know if any of them
help you out.
1.Please ensure there are no antivirus is installed and is
running on the background.This might sometimes clash with the
Installation.
[This is really useful. Since windows is so buggy I would think almost everyone is running some kind of antivirus program. And I searched their help system, and didn't find anything under virus or antivirus, nor does their installation mention it.]
2.The reason could be an IRQ clash.
a.shut down the system
b. remove the USB card
c.Start the system
d.Shut it down again
e.Insert the USB card
f.start the system
g.Insert the device with media
h.Install drivers
[If it were an IRQ clash, the other OS installations
would likely not work also. Also I never mentioned a USB card. As
most motherboards have USB now, this seems like useless at best
advice.]
I'm sure your questions are answered.
[This is a really puzzling statement. Perhaps just odd
english, but it seems wildly optimistic.]
Thanks in advance.
Have a great day!
Naveen
Auto-Response02/18/2003 10:39 PM
, Thank you for your interest in your Dazzle* 6-in-1 Card
Reader/Writer. Your issue is still unresolved and is being worked
on by our staff. In the meantime, these Answers were
automatically selected for your consideration. If your issue is
addressed in our public Answers, a solution link should be listed
below. If no solutions are listed or the solutions do not match
your issue, there were no public Answers related to your issue. A
Customer Service agent will be responding to you shortly. If one
of the Answer links below resolves your issue, please close this
incident.
> Please visit the following links:
Title: Optimal Computer Performance for PCs
Link:
http://scmmicro.custhelp.com/cgi-bin/scmmicro.cfg/php/enduser/std_adp.php?p_faqid=301
Title: Drive letter assignment for USB Card Readers in Windows
2000 & XP on a LAN
Link:
http://scmmicro.custhelp.com/cgi-bin/scmmicro.cfg/php/enduser/std_adp.php?p_faqid=1400&p_created=1027439721
Title: Safe ejection of removable media in Windows 2000
Link:
http://scmmicro.custhelp.com/cgi-bin/scmmicro.cfg/php/enduser/std_adp.php?p_faqid=1399&p_created=1027437076
Title: Locating the part number for your Dazzle installation
CD
Link:
http://scmmicro.custhelp.com/cgi-bin/scmmicro.cfg/php/enduser/std_adp.php?p_faqid=1707&p_created=1044398908
Customer02/18/2003 10:39 PM
When I use the install cd and reboot my system, the system hangs. I tried the previous configuration, but that hangs also. I tried safe mode, and uninstalled the device, and then unplugged the device. I successfully uninstalled via the device manager. When I reboot into normal win 2000 sp3, the system hangs. I am really in a bad way now.
I remember similar problems when I did this the last time I installed win 2000, but I did something clever to successfully install the reader. Any ideas?
It would be ideal to send email to lopgok@hotmail.com, as it is difficult to read email, when I cannot boot my main computer.
thanks,
Turbo
To: smmicro4@custhelp.com
Subject: Re: Windows 2000 professional [Incident:
030218-000454]
[===> Please enter your reply below this line
<===]
Gee, I would like to go to FAQ 1203, but your web page is broken. I tried it under the latest Mozilla as well as the latest IE, and nothing happened when I typed in 1203 to the FAQ box. I even turned Java and javascript on on Mozilla, and turned down the security on IE. I do simple web design, I am happy to consult on making working and portable web pages. I would encourage to test your pages with Opera, Lynx, Mozilla, as well as IE on windows, Linux, mac os X for starters.
I did read the ZiO! link, and it was somewhat useful. Too bad I couldn't find anything like it for the 6-in-1 reader when I was hosed up.
I am glad you like my website. I am sorry you don't feel in your heart of hearts that when a piece of hardware/software renders a computer unusable that they should be called weasel of the month. I have at least 10 computers here, and quite a wide variety of hardware. I have never had 3rd party software render my computer OS unusable before. I have modest skill writing software, with over 20 years of experience, as well as working on the very first e-commerce system, and I have never seen such damaging software. I would suggest a course in basic software engineering for your developers.
I find your message 'Give us one more try on Win2K.I'm sure you will find us good.' really amusing. Do you think I want to scrub my 15k RPM SCSI drive of a working OS (win XP) that took me well over 10 hours to install and load all the apps, just so I can re-install win 2000, and go through the process of patching it, and installing my apps, just for the privilege of wedging my system again (as it has done every time) with your system-destroying software? Do you know what a production system is? I run my main computer 24*7. I don't have time to reload a OS, nor do I feel that plugging in a new 15k RPM drive and loading win2000 is a really fun process.
Having to use the recovery console on win2000 should give you folks a clue that something is seriously wrong with your software. Fortunately, Microsoft included enough drivers with win XP that I don't have to use your death-inducing cd software installer.
If you folks want to pay me to test your software, I am happy to do so. I will get a dedicated machine to do so, so I won't disrupt my main computer operations. I have a variety of single and dual processor systems, with Intel and AMD chips and a variety of BIOS's and clock rates.
I also do software engineering consulting. My rates are reasonable.
Turbo
[===> Please enter your reply above this line
<===]
If your issue remains unresolved, please update this question
here.
Subject Windows 2000 professional
Discussion Thread
Response (Naveen)02/28/2003 06:09 AM
Dear Turbo,
I understand your frustrations loud and clear.I perfectly justify
them.The answers are some of them which have helped people who
sounded the exact way your mail read.It sure has helped
them.
We really want to help you out and make you feel that you did
make a right choice on purchasing Dazzle.
Here are some notes on Win2000 Problems on Installation.
1.Please go through FAQ ID 1203
2.Title: During the ZiO! Installation I get a blank screen URL:
http://scmmicro.custhelp.com/cgi-bin/scmmicro.cfg/php/enduser/std_adp.php?p_faqid=475&p_created=1003258931
Thank you.
Good day!
Naveen
P.S -I really like your creativity(I mean it!!!). and I did go
through your website.But,Heart of hearts I feel we do not deserve
that place.Give us one more try on Win2K.I'm sure you will find
us good.I'm keeping this mail unresolved to make sure I will sort
out your issue.
Customer02/27/2003 07:58 AM
[... repeated stuff
deleted...]
This was my first external hard drive. It features USB as well as firewire. It has a 120gb 7200 rpm IDE hard drive. It has a power LED as well as an activity LED. One missing feature is a power switch. You have to yank a cord to turn it off, which is a hassle. I used it exclusively with the firewire interface, which worked quite well. After the 1 year warranty ran out, I opened it up, and put in a 200gb hard drive. The case was not designed for this. Two screws that have to be removed to access the inside are under the manufacturers sticker on the underside. It was difficult to open up, and there was some shielding that was around the electrical connections that had to be gently removed and then reattached. It does have some vents on the bottom to help with cooling.
This enclosure is USB only. It has a power switch, a power LED, and an activity LED. There are some vents on the bottom, but they press against the top of the hard drive, and seem mostly useless. It is very easy to install a hard drive, unlike the Western Digital WD1200. It also takes up quite a bit of space with the 'X' shaped exterior. At least it puts an air gap around much of the hard drive to hopefully aid cooling.
This enclosure is USB as well as e-SATA. It has a power switch, as well as an I/O bracket and adapter from an internal SATA port, to provide an e-SATA port in case your motherboard doesn't have one. This enclosure has a very quiet cooling fan. It is very easy to install a hard drive, though there are a bunch of screws to contend with. In the interest of minimizing vibration, the hard drive secures with screws on the bottom, which are surrounded with silicone washers. Overall, I think this is the best 3.5" hard drive enclosure.
If you have comments or suggestions, Email me at turbo-www@weasel.com
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