SCSI Ancient and near obsolete Hardware!!!

[aggro_mix]

Maybe a bit OT but I wish someone would make a DMA capable IDE interface for the zorro slots. Is it really that hard?

[jj]

The first drive I bought was a 256mb HDD , ues mb not gb lol
and it cost me over £300.  Still got it, still works.  Remember wondering how I would ever fill that on my Amiga lol.

Need to buy a new HDD for my PC cause my 250gig HDD is full lol

[Ral-Clan]

Apparently you can buy IDE to SCSI convertors.  This allows you to use cheap IDE devices with a SCSI controller.  I'm not sure how you would terminate these drives though (maybe there is a jumper on the convertor).

[itix]

SATA is still inferior to SCSI on areas like multitasking.

What SATA and SCSI have to do with multitasking?

[Tomas]

What SATA and SCSI have to do with multitasking?

ata and sata use more cpu cycles when you have multiple transfers going on at the same time. This would cause a noticeable performance impact on a busy web server or similar.

[Piru]

ata and sata use more cpu cycles when you have multiple transfers going on at the same time

Why is that?

[Tomas]

Piru wrote:

ata and sata use more cpu cycles when you have multiple transfers going on at the same time

Why is that?

here is a quote i found:

For the user who is performance-conscious, who will be doing real multitasking, using many devices at once, doing heavy development work, supporting multiple users at once on the machine, or who otherwise wants the best and is not afraid if it costs a few hundred dollars more, SCSI is the obvious choice. SCSI offers the most flexibility, the most choice of peripherals, and the best performance in a multitasking or multi-user environment.

I dont know the real technical background on why though.. I do however have it verified by personal experience from using both.
Same thing goes for SATA.. It is slower and use more cpu than the SCSI equalent if you have multiple disk with heavy disk access at the same time.

I guess this explains some of it:

ATA drives are cheaper than SCSI or Fibre Channel drives and there's a reason. SCSI and FC drives use a processor for executing the commands and handling the interface and a separate processor controlling the head positioning through servos. ATA drives use a single processor for both which means that if the rotational positioning requires more adjustments due to factors such as rotational vibration or wear, more processor time will be dedicated for that which can affect the performance of the drive. Because of this, you will usually see a lower RPM for the ATA disk drive and also a shorter warranty period. But it is cheaper and can be a very good, economical solution for many environments and applications.

[Piru]

For the user who is performance-conscious, who will be doing real multitasking, using many devices at once, doing heavy development work, supporting multiple users at once on the machine, or who otherwise wants the best and is not afraid if it costs a few hundred dollars more, SCSI is the obvious choice. SCSI offers the most flexibility, the most choice of peripherals, and the best performance in a multitasking or multi-user environment.

SCSI is hideously more expensive than SATA, and the difference has only gotten bigger. The things that traditionally gave SCSI an edge (such as SCSI TCQ) have long since been adopted for ATA and SATA (in form of NCQ). While SCSI TCQ has longer queue, in reality the performance benefit from it is minimal.

While SCSI might offer better single drive performance (15kprm drives), the costs of such system compared to nice SATA RAID setup makes SATA more affordable and attractive.

I'm not denying SCSI has it's special uses, but in generic use servers SCSI has been dead for years.

In practice SATA has replaced SCSI in many cases. This is why I consider my argument valid.

ATA drives are cheaper than SCSI or Fibre Channel drives and there's a reason. SCSI and FC drives use a processor for executing the commands and handling the interface and a separate processor controlling the head positioning through servos. ATA drives use a single processor for both which means that if the rotational positioning requires more adjustments due to factors such as rotational vibration or wear, more processor time will be dedicated for that which can affect the performance of the drive. Because of this, you will usually see a lower RPM for the ATA disk drive and also a shorter warranty period. But it is cheaper and can be a very good, economical solution for many environments and applications.

This has absolutely nothing to do with system CPU usage. The actual data is transferred using DMA, and while the drive is busy the CPU is 100% free for other uses.

[Tahoe]

Piru wrote:

While SCSI might offer better single drive performance (15kprm drives), the costs of such system compared to nice SATA RAID setup makes SATA more affordable and attractive.

Agreed, specially looking at the current SATA drive prices. These have been falling really rapidly.

Don't forget the Raptor drives; these 10K RPM SATA drives offer more punch then any regular SATA disk. Although; the larger the disk; the faster the transfers (generally speaking). Specially the new perpendicular recording technology has been a boost. My Seagate 7200.10 series 500GB disks in RAID-0 are very fast, only slightly slower then my OS disks (Raptor 146GB 10K RAID-0)

I'm not denying SCSI has it's special uses, but in generic use servers SCSI has been dead for years.

Sorry, I have to disagree. Take a look at HP servers; most of them still run SCSI. The new G5 series Proliant now offer a choice of SATA or SAS backplanes; but the G4 (only EOL for about 9 months) is still 100% SCSI.

In practice SATA has replaced SCSI in many cases. This is why I consider my argument valid.

Don't forget that SCSI drives (even the new ones) are much more robust then SATA/ATA disk. We have a SAN at work which is built around very fast SCSI disks in an array and cheap; dump storage in an array of SATA disks. (best of both world so to say, 1.5TB SCSI, 7.5TB SATA)
The SATA drives fail about TWICE as much as the SCSI disks.
(if one scsi drive fails a year; at least 2 sata disks will fail)

[X-ray]

Fibre Channel is the current word in servers.

[terminator4]

I wasn't talking about it being hardware type or not.  
Someone said SCSI is dead - generic thing to say - the answer is "No its not dead" to that.  Both Fiberchannel and iSCSI are around.
SCSI is dead for home market b/c no one here will spend more than $1000 on a computer.  In fact many users here expect stuff for less than $200, in which case as I mentioned before publicly they should not call themselves amiga users and go back to PC.  
Amiga market has always been small and no one will offer any hardware for small amounts/margins.  I do know there are many so called dealers whose generic background should be nothing but a shame (no need ot mention names, they know who they are).
You see the results with OS 4 and Amiga Ones - one good reason why so few boards were made, because few amiga users would pay money to get theirs preordered.  Hence few were made.  Small market - no economies of scale - big price.  Apple is another example of that.  Its not that their hardware is something special.
SCSI - well its expensive compared to IDE and most users would not notice the difference anyways.

adolescent wrote:
iSCSI isn't a hardware type, but a network protocol.  (For instance, you will not find a iSCSI HD or tape drive.)