Is SCSI hdd`s really worth the money?

[Wiken]

The reason for this topic is that i had an seagate barracuda 9,1gig scsi disk, but all of a sudden it died.And thank god i still had guarantie on it.
And those i bought it from they say that they will either give me a new 9,1gig scsi
u2w or an Ibm 45gig ata100 disk.

what should i take? =)

i really want lots of space though, but kwality before quantity

[Walrus]

Wiken: If you have a spare IDE channel, GO FOR THE IBM!!!! It's more reliable in my experience as a network consultant, and it SCREAMS.

[KRSESQ]

Definitely the IBM. scsi's only advantage over modern ATA 100 drives is they can handle multiple user requests simultaniously, which makes them ideal for network environments. For a single user on a non-networked desktop, the advantage disappears.

P.S. make sure your IDE controller is ATA 100 compatable or you might need a seperate controller card. Even then, I'd still be inclined toward the IBM.

[This message has been edited by KRSESQ (edited 13 September 2000).]

[Walrus]

KRSESQ: Actually, the main advantage of SCSI is handling multiple devices on a single channel better, (accessing one device on the channel does not block the others from being accessed) and the number of devices on the channel. As for U/100... Even if you have an Ultra/33 controller... I'd still go for the IBM drive. It may saturate the available bandwidth, but 33mb/sec is quite fast for nearly anything.

[bastioned]

Believe me, there´s a huge difference between using a good UW SCSI HD than an IDE one. This is my experience: after many types of IDE HD ( 10, 20, 40 GB all of them UDMA66 ) I couldn´t capture full size MJPEG video ( using Morgan MJPEG codec handled by the processor ) , after 20 seconds or so it started to drop frames. When I changed to U2 SCSI Seagate Cheeta ... voilá! no drop frames at all, and I had spare processor power to other things.
The point is: SCSI reaches more transfer rates than IDE ,period, and consumes less CPU power , by far, than IDE. Make your choice, SCSI doesn´t have the fame for nothing...

[Wiken]

Thanx to everyone for all good answers!
I have now decided to go for the Ibm 45gig ata100 (and i do have a ata100 combatible mainboard) its an Be-6II rev1.2 in fact

The only reason for this question, was simply what is the best deal for me, and ive got it all answered :P

Bastioned: and to you, ill guess the framedrop problem depends very much on how you have setup your machine to, i can do 2 hour capture with non drop frames with my two ata66 disks.

[Walrus]

bastioned: I LOVE SCSI as a rule, but I can't help but think something is not setup properly on your system. Is DMA enabled? Are you using your hard drives on seperate channels? I have 4 hard drives: 1 Ultra-2Wide SCSI (IBM 7200 rpm 9.1 GB), 1 IBM 20 GB 7200 RPM IDE, and 2 IBM 20 GB 5400 RPM IDE. ALL of them can easily handle full resolution HuffYUV transfers (which uses ~ 10MB/sec and gobs of CPU power), and the 7200 RPM 20 GB IDE actually OUTPERFORMS the 7200 RPM U2Wide SCSI. (~ 18 MB/sec sustained vs 13 MB/sec sustained) That all said, I would never replace SCSI because it allows me to have an external chain of devices including my DVD-ROM, my CD-RW, my Onstream SC-50 tape drive, and occasionally my zip drive. If I had limitless money, I'd probably go all SCSI so I can do it all with a single IRQ, but I don't have limitless money, and my current setup works REALLY nicely.

[Sillyname]

You know all these posts about freeing up resources to combat dropped frames? The only advantage that SCSI still has over IDE is that it uses less CPU. So you really don't have to worry about systray crap as much. But!!! 45 GB is ALOT of space! And it's an IBM!

What a strange question to post...

------------------
Deep is not the root word of depression.

[mynx]

Walrus: I also love SCSI. Having 6 scsi devices and my U2W drive all one one IRQ. I don't understand why you only get 13 MB/Sec sustained with it. I get over 18MB/sec with my U2W drve and 13MB/sec IDE.

[Walrus]

mynx: The reason why the IDE outperforms the SCSI on my system is quite simple: The IDE is about a year newer. (newer generation drive) The Ultra2Wide is no slouch at all, but nor is the IDE. As for CPU utilization... as long as the driver is decent, UDMA has about the same CPU utilization as any SCSI. Again, SCSI is the best for having a ton of devices on one IRQ. (and for external, high end RAID, etc) That said, for 90% of the people (including us digital video freaks) modern IDE drives work just as well and is far cheaper.

[This message has been edited by Walrus (edited 14 September 2000).]

[bastioned]

Sorry guys, I forgot to add something to the post: I wasn´t actually using the RR-G to capture, I was using an Aver 98, with the BT 848 codec, and you all know that this cards don´t have hardware for real time capture, it´s handled entirely by the CPU. The point is that because SCSI used far less CPU power than IDE, I could capture with this card without dropped frames, something I simply couldn´t with IDE.

[Eric VanHeest]

I capture to IDE drives with software compression that uses up 95% of the processor during capture (HuffYUV on a 400-ish MHz machine), and have no problems. If a machine is set up properly, there won't be any problems with IDE processing, and that's really all there is to it, unless you consider less than 5% processor usage (including kernel) to be "far more" than SCSI. If your machine is wasting processor playing with your IDE devices, the system isn't configured correctly, and although switching to SCSI will "magically" fix this problem (since SCSI does not need to be configured to avoid PIO), that doesn't mean that the SCSI is "better" (per se), just easier to get set up properly for maximum performance.

[Grigory]

Bastioned:

How much was CPU utilization in case of SCSI and DMA?
I have the same few % value for ~10 Mbytes/sec data rate.

It depends on DMA drivers you use. With Intel chipset it is better to use MS drivers that come with win 98, win NT and win2k. All other Bus mastering drivers are not working for video. It may be difficult to turn DMA ON on WinNT, because some drives refuse to work.

Direct comparison:
9.1 GB UWSCSI drive on server at my job works slower, produces much more noise and takes exactly the same CPU power that modern Fujitsu drive. I am just not saying about specific model of IBM, which can write and read x2 faster.

Concerning BT848 card and software compression. The ability to compress in realtime depend on:
1. Video content - more details produce higher bitrate and require more CPU power. You have to compare drives performance on the same video fragments.
2. Capture format. YUY2 is the best for MJPEG captures, but BTUV (4:1:1) provides almost the same speed. RGB is the slowest, because the codec has to convert this to YUY2.
3. Preview mode of capture application. For whatever reason, overlay is almost always better than Preview mode in Vidcap32. This, however, places heavy load on PCI bus - the data flows to CPU and video bus simultaneously. You can turn OFF both modes to get full data flow in CPU only.

I am able to capture 720x576 YUY2 uncompressed with software raid of Fujistu drives under NT 2000:
one 10.2 GB MPC drive as Primary slave
one 17 (10.2 used for raid) Fujitsu MPE drive as primary master on IDE66 built-in HPT controller of ABIT BP6. 21 MB/sec data writing take 6% CPU time.
Writing the same video as 3.5 MB/sec data stream can take only 2% CPU time, which cannot lower the coeec performance.

With PICVideo or Mainconcept MJPEG codecs I am able to compress up to 3.5 MB/sec output data rate full size 720x576 video on Celeron 500, regardless of IDE drive I use.

I do not see any advantage of SCSI drives, except the specialized applications.
Even the argument that SCSI allows to connect multiple devices is not as strong - I am using 7 IDE devices now and still have one connector free. And, I have USB for all these printers, scanners, ...

The system contains DV Raptor, Hollywood+ decoder, network PCI card, ISA modem and soundcard and G400. Not all of them get single IRQ, but all work together under 98 and 2000.
Grigory

[bastioned]

Come on, men, don´t fool yourself, if IDE is the "panacea", then why every single server in this world ( I mean real servers, not the rigs at home) are built around SCSI HD? I have been for 7 years working as a Systems Expert and Consultant, have beeing in many enterprises , developed database intensive applications ( Oracle, Lotus ) and IDE is simply not Capable of handling any multitasking enviroment. Of course, for the matter that concerns us, that is, home-based PCs, IDE is a good option, and the reason why it works out good is because the high transfer rates it achieves in burst modes ( this mode is used when capturing) , try to read even only a single bit from the HD while capturing in a IDE and in a SCSI and you´ll see the difference.

[Walrus]

bastioned: The reasons why high end servers often use SCSI are for the following reasons:
Better support for SCSI than IDE in some high end server environments, more devices per channel without the stupid command blocking on IDE channels, faster drives on the very high end, better RAID available with better caching if you can afford the controllers(which is leads to a great deal of theoretical advantages to SCSI in multitasking environments). However, these advantages are falling away. Modern high end IDE drives are only barely slower than the highest available SCSI drives, primitive RAID is now available for IDE quite cheap, and DMA mode removes the CPU utilization problem as long as the driver is written correctly. With Serial-ATA (assuming it works) on the horizon the days of channel problems with IDE may be going away as well. I do agree for the very highest end servers where every scrap of speed counts and money isn't an issue, SCSI is the way to go, however in most other cases IDE has the advantage due to it's severely lower cost.