IDE vs. SCSI

Finx · 06-12-2001, 06:42 PM

Some say SCSI is better , Some say IDE is. I think IDE is slowly taking over that margin SCSI had over it. This is were you can all dispute what you think , please leave out the weapons! lol

- Finx

bdunosk · 06-15-2001, 07:07 AM

I think you're going to get everyone defending their setup here... but, anyway...

I have all-SCSI, and I think the main disadvantage is price. I definitely like it better than my previous IDE setup, it *seems* to be faster. I never benchmarked. :P

One thing I can do w/ SCSI that I can't do easily w/ IDE - when I formatted my harddrive, it was much faster to copy stuff from my backup CD (tons of MP3's, etc.) - I had 2 CD's going at a time and my system wasn't in "super-IDE-lag mode." Kind of a weak reason to get SCSI, though. :P

Finx · 06-16-2001, 12:29 AM

Thats interesing - I dont know anything about it and had a decent amount of money to get an array of SCSI to test out but I blew it on new Salomon skates =[ I still might do it this summer when money comes in but I dont understand what the whopping deal is or if you have to do anything special or different , and if the SCSI mobos have IDE to? thanks for anyones help

- Finx

Joe · 06-16-2001, 01:03 AM

SCSI - Best over all performance, most scale'ble, is the best interface for HD's currently available for a high end consumer market.

IDE - best price, poor ATA interface ( Uni Directional, not Bi like SCSI), poor multiple device read/write times.

Finx · 06-16-2001, 01:31 AM

Interesting - In the Pro Chat I mentioned something of SCSI and some evil villan ( name remains unknown......) said it was terrible and really slow and bad. Don't understand. Also do the mobos have anything special to configure and do they have IDE as well as SCSI? Also is the Raid version motherboards the same thing as an SCSI board?
sorry for all the questions just a newbie to SCSI and drives i guess. Thanks

- Finx

Darkhorse · 06-16-2001, 12:39 PM

Finx,

SCSI is one thing I do know a lot about.

My server is using a SCSI array. SCSI has a few advantages over IDE.

Depending on the which type you get it can support between 7 & 15 devices off a single port. Unlike IDE, SCSI uses very little processing time to do reads or writes.

SCSI adapters & nearly all devices made in the last 5 years support what is call 'disconnection'. What this means is say you have 3 HD's on a single SCSI chain & connect a activity LED to each one. Then pump large files to each drive at the same time you will see that all the drive led's seem to be on at the same time. What is happening is that the SCSI controller issues a command to each drive & then 'disconnects' enabling it to send a command to another drive, and so on. when the drive has completed the task it sends a ready signal to the controller which reconnects and sends more data or whatever.

Unlike IDE - SCSI has alot more standards/interfaces. It also supports external devices, My server is running 6*9.1GB drives (RAID 5) using a RAID controller. On another SCSI controller I've got 2 internal CDROMS & and a external DLT 35/70 tape drive.

It's usually cheaper to get a SCSI controller on a PCI card than to get one built onto a Mobo.

Raid 0, 1 and 0+1 on IDE are the same as they are for SCSI. SCSI RAID controllers also offer RAID 5 which is a compromise between RAID 0 & 0+1.

SCSI Controllers & SCSI RAID controllers are not the same thing - there is a huge cost difference. As there is between anything SCSI & IDE. SCSI devices have a lot more intelligence on board than IDE drives.

Sorry if I've rambled on, this is quite a complex topic.

Finx · 06-16-2001, 10:57 PM

Thankyou very much Dark - That helped alot =] This summer I am going to get an SCSI array with a controller. But my last question is what does a raid version of a motherboard do different than a normal , such as the normal KK266 vs. the KK266-R?
thanks again.

- Finx

Darkhorse · 06-17-2001, 04:21 AM

If I've understood your question.

If you attach 2*40GB HD's to either a normal IDE/SCSI controller you are going to end up with at least 2 drive letters (not allowing for NT type configs).

With a RAID controller (depending on how you set it up) the data is striped across all disks. So as far as the OS is concerned the 2*40GB HD's look like 1 80GB HD. This is a very basic explaination. This also gives you a performance boost. In theroy the more drives you use the bigger the performance boost. Although in practice the available bandwidth tends to max out after a certain point.

Adaptec have a good white paper on RAID levels here.

Adaptec do entry level SCSI RAID controllers starting from $500. Your then going to have to buy SCSI drives which tend to cost about 25% more than IDE.

I'm not sure the cost is worth it for individual use. I bought my server setup to alow me to work with similar hardware to my clients.

My server setup is:
PIII 500Mhz
256MB RAM
6*9.1GB UW SCSI (RAID 5)
Compaq 3200 Scsi Raid Controller with 64MB of cache
Adaptec 2940UW SCSI controller
1 * Plextor 32x CDrom
1 * Plextor 40x CDrom
1 * 35/70GB HP DLT tape drive
Running Novell Netware 5.1

So in my server setup one of the six HD's can fail but my server can still access the storage, just at reduced performance. I replace the failed drive - where upon the new disk is repopulated automatically with data rebuilt from the other five disks checksum information. Because of the way RAID 5 works you tend to loose about 1 disks worth of storage. So I only get 5*9.1Gb's instead of 6*9.1Gb's.

Sorry another long post.

Hope this helps.

Finx · 06-17-2001, 11:46 AM

Ahhh that helps , thanks man , but I guess I will need to come prepared with alot of money when im setting up my SCSI system. But if the cards are around 500 then why are the motherboards with RAID only 140-250?

Darkhorse · 06-17-2001, 01:18 PM

Are you talking SCSI RAID or IDE RAID?

Finx · 06-17-2001, 02:35 PM

I am not sure it just says raid

- Finx

Darkhorse · 06-18-2001, 03:52 AM

I suspect it's IDE RAID. I've never seen a Mobo being sold (seperately) with onboard SCSI RAID. The only units I've seen with onboard raid tend to be Compaq Proliant servers etc.

imagex · 06-18-2001, 06:47 PM

I know for a fact that the abit kt7 raid & the msi k7t raid both use ide raid.

jtroutma · 08-29-2001, 12:08 AM

Special note:

If a motherboard SAYS it has RAID yet does NOT mention SCSI then automatically it is an IDE RAID solution. Very few motherboards have on-board SCSI adapters (let alone SCSI RAID adapters

For most of the standard boards you hear about (eg. Abit, ASUS, EPoX, Gigabyte, MSI, etc.) those almost always have IDE RAID on them when they mention RAID. Its not until you get into the IMHO "super" MB that you start to see on-board SCSI solutions.

My main system is completely SCSI and is, for the most part, wonderful. I have 4 HDD (3 of them in RAID 0), 3 CDROM drives, and a SCSI ZIP drive all running on an Adaptec 2940U2W. The best thing I love about this setup is that all that is running on ONE IRQ and is very fast!! (Try and do that with IDE

Anyways I am done rambling myself

Any more questions?

06-12-2001, 06:42 PM	#1
Finx Foo's Been Banned Join Date: Jun 2001 Location: Glenview , Illinois Posts: 35	IDE vs. SCSI Some say SCSI is better , Some say IDE is. I think IDE is slowly taking over that margin SCSI had over it. This is were you can all dispute what you think , please leave out the weapons! lol - Finx

06-16-2001, 01:03 AM	#4
Joe The Pro/Life Support System Join Date: Dec 1999 Location: Denver, CO Posts: 4,041	SCSI - Best over all performance, most scale'ble, is the best interface for HD's currently available for a high end consumer market. IDE - best price, poor ATA interface ( Uni Directional, not Bi like SCSI), poor multiple device read/write times. __________________ Joe - I only take this hat off for one thing... ProCooling archive curator and dusty skeleton.

06-18-2001, 06:47 PM	#13
imagex Cooling Savant Join Date: Mar 2001 Location: south FL Posts: 220	I know for a fact that the abit kt7 raid & the msi k7t raid both use ide raid. __________________ Overkill'n Overclock'n Hybrid Mobile Solutions

08-29-2001, 12:08 AM	#14
jtroutma Cooling Savant Join Date: Aug 2001 Location: SLO, CA Posts: 837	Special note: If a motherboard SAYS it has RAID yet does NOT mention SCSI then automatically it is an IDE RAID solution. Very few motherboards have on-board SCSI adapters (let alone SCSI RAID adapters For most of the standard boards you hear about (eg. Abit, ASUS, EPoX, Gigabyte, MSI, etc.) those almost always have IDE RAID on them when they mention RAID. Its not until you get into the IMHO "super" MB that you start to see on-board SCSI solutions. My main system is completely SCSI and is, for the most part, wonderful. I have 4 HDD (3 of them in RAID 0), 3 CDROM drives, and a SCSI ZIP drive all running on an Adaptec 2940U2W. The best thing I love about this setup is that all that is running on ONE IRQ and is very fast!! (Try and do that with IDE Anyways I am done rambling myself Any more questions? __________________ Athlon64 X2 4200+ @ 2.5Ghz (250FSB x 10) OCZ VX 1GB 4000 @ 250FSB (6-2-2-2 timmings) DFI LANParty nForce4 Ultra-D SCSI Raid 5 x (3) Cheetah 15K HDDs LSI Express 500 (128MB cache) OCZ PowerStream 520W PSU ATI X850XT PE (Stock) DTEK WhiteWater + DTEK Custom Radiator Eheim 1250

06-15-2001, 07:07 AM	#2
bdunosk Cooling Neophyte Join Date: May 2001 Location: Cincinnati, OH Posts: 93	I think you're going to get everyone defending their setup here... but, anyway... I have all-SCSI, and I think the main disadvantage is price. I definitely like it better than my previous IDE setup, it seems to be faster. I never benchmarked. :P One thing I can do w/ SCSI that I can't do easily w/ IDE - when I formatted my harddrive, it was much faster to copy stuff from my backup CD (tons of MP3's, etc.) - I had 2 CD's going at a time and my system wasn't in "super-IDE-lag mode." Kind of a weak reason to get SCSI, though. :P

06-16-2001, 12:29 AM	#3
Finx Foo's Been Banned Join Date: Jun 2001 Location: Glenview , Illinois Posts: 35	Thats interesing - I dont know anything about it and had a decent amount of money to get an array of SCSI to test out but I blew it on new Salomon skates =[ I still might do it this summer when money comes in but I dont understand what the whopping deal is or if you have to do anything special or different , and if the SCSI mobos have IDE to? thanks for anyones help - Finx

06-16-2001, 01:31 AM	#5
Finx Foo's Been Banned Join Date: Jun 2001 Location: Glenview , Illinois Posts: 35	Interesting - In the Pro Chat I mentioned something of SCSI and some evil villan ( name remains unknown......) said it was terrible and really slow and bad. Don't understand. Also do the mobos have anything special to configure and do they have IDE as well as SCSI? Also is the Raid version motherboards the same thing as an SCSI board? sorry for all the questions just a newbie to SCSI and drives i guess. Thanks - Finx

06-16-2001, 12:39 PM	#6
Darkhorse Cooling Savant Join Date: Jun 2001 Location: UK Posts: 103	Finx, SCSI is one thing I do know a lot about. My server is using a SCSI array. SCSI has a few advantages over IDE. Depending on the which type you get it can support between 7 & 15 devices off a single port. Unlike IDE, SCSI uses very little processing time to do reads or writes. SCSI adapters & nearly all devices made in the last 5 years support what is call 'disconnection'. What this means is say you have 3 HD's on a single SCSI chain & connect a activity LED to each one. Then pump large files to each drive at the same time you will see that all the drive led's seem to be on at the same time. What is happening is that the SCSI controller issues a command to each drive & then 'disconnects' enabling it to send a command to another drive, and so on. when the drive has completed the task it sends a ready signal to the controller which reconnects and sends more data or whatever. Unlike IDE - SCSI has alot more standards/interfaces. It also supports external devices, My server is running 6*9.1GB drives (RAID 5) using a RAID controller. On another SCSI controller I've got 2 internal CDROMS & and a external DLT 35/70 tape drive. It's usually cheaper to get a SCSI controller on a PCI card than to get one built onto a Mobo. Raid 0, 1 and 0+1 on IDE are the same as they are for SCSI. SCSI RAID controllers also offer RAID 5 which is a compromise between RAID 0 & 0+1. SCSI Controllers & SCSI RAID controllers are not the same thing - there is a huge cost difference. As there is between anything SCSI & IDE. SCSI devices have a lot more intelligence on board than IDE drives. Sorry if I've rambled on, this is quite a complex topic.

06-16-2001, 10:57 PM	#7
Finx Foo's Been Banned Join Date: Jun 2001 Location: Glenview , Illinois Posts: 35	Thankyou very much Dark - That helped alot =] This summer I am going to get an SCSI array with a controller. But my last question is what does a raid version of a motherboard do different than a normal , such as the normal KK266 vs. the KK266-R? thanks again. - Finx

06-17-2001, 04:21 AM	#8
Darkhorse Cooling Savant Join Date: Jun 2001 Location: UK Posts: 103	If I've understood your question. If you attach 240GB HD's to either a normal IDE/SCSI controller you are going to end up with at least 2 drive letters (not allowing for NT type configs). With a RAID controller (depending on how you set it up) the data is striped across all disks. So as far as the OS is concerned the 240GB HD's look like 1 80GB HD. This is a very basic explaination. This also gives you a performance boost. In theroy the more drives you use the bigger the performance boost. Although in practice the available bandwidth tends to max out after a certain point. Adaptec have a good white paper on RAID levels here. Adaptec do entry level SCSI RAID controllers starting from $500. Your then going to have to buy SCSI drives which tend to cost about 25% more than IDE. I'm not sure the cost is worth it for individual use. I bought my server setup to alow me to work with similar hardware to my clients. My server setup is: PIII 500Mhz 256MB RAM 69.1GB UW SCSI (RAID 5) Compaq 3200 Scsi Raid Controller with 64MB of cache Adaptec 2940UW SCSI controller 1 Plextor 32x CDrom 1 * Plextor 40x CDrom 1 * 35/70GB HP DLT tape drive Running Novell Netware 5.1 So in my server setup one of the six HD's can fail but my server can still access the storage, just at reduced performance. I replace the failed drive - where upon the new disk is repopulated automatically with data rebuilt from the other five disks checksum information. Because of the way RAID 5 works you tend to loose about 1 disks worth of storage. So I only get 59.1Gb's instead of 69.1Gb's. Sorry another long post. Hope this helps.

06-17-2001, 11:46 AM	#9
Finx Foo's Been Banned Join Date: Jun 2001 Location: Glenview , Illinois Posts: 35	Ahhh that helps , thanks man , but I guess I will need to come prepared with alot of money when im setting up my SCSI system. But if the cards are around 500 then why are the motherboards with RAID only 140-250?

06-17-2001, 01:18 PM	#10
Darkhorse Cooling Savant Join Date: Jun 2001 Location: UK Posts: 103	Are you talking SCSI RAID or IDE RAID?

06-17-2001, 02:35 PM	#11
Finx Foo's Been Banned Join Date: Jun 2001 Location: Glenview , Illinois Posts: 35	I am not sure it just says raid - Finx

06-18-2001, 03:52 AM	#12
Darkhorse Cooling Savant Join Date: Jun 2001 Location: UK Posts: 103	I suspect it's IDE RAID. I've never seen a Mobo being sold (seperately) with onboard SCSI RAID. The only units I've seen with onboard raid tend to be Compaq Proliant servers etc.

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