firewire vs scsi....

Discussion in 'General Mac Discussion' started by krossfyter, Jul 6, 2002.

  1. krossfyter macrumors 601

    krossfyter

    Joined:
    Jan 13, 2002
    Location:
    secret city
    #1
    okay... i want to learn about about this...

    which one is faster..better.. and why?

    state your argument. im all ears. someone brought up the argument to me that scsi is faster and better... but i was a little upset becasue im not that educated enough in this. all i know is that firewire is fast enough to me firewire 2 is coming out and firewire is easier to mess with.

    spill it homespanks!
     
  2. Nipsy macrumors 65816

    Nipsy

    Joined:
    Jan 19, 2002
    #2
    Re: firewire vs scsi....

    SCSI is still the best system for out and out speed. SCSI is fast because the read/write instructions can be sent to up to 15 drives per channel concurrently. IDE/ATA cannot do this. I have an ATTO UL3D Dual Channel U160 card rigged to a 12 drive RAID, and I can get 215MB/S easily. This is saturation of the PCI bus. Of course, I don't work with video, so this rig is wasted on me.

    SCSI, while faster, and very reliable, can be a beast to setup properly. Different generations of SCSI have different types of cables. Drives need specific jumpering, termination can be the cause of endless hair pulling, etc. Plus, SCSI hardware is pricey. My setup cost well more than my computer, and I will likely sell it after MWNY.

    SCSI Card $400
    SCSI Cabling $225
    SCSI RAID Box $400
    SCSI Drives $1200
    Having a boss give it to you to take home:
    Priceless

    I don't have alot of experience with Firewire, but what I have used has been flawless & easy, if not extremely fast. I haven't really investigated large FireWire systems, because the FireWire bus is inherently slower than dual channel SCSI.

    The lastest toy I've acquired is a SIIG ATA 133 RAID card. I now have a 240GB RAID for about $375, which gives me 110MB/S. This is larger than my SCSI RAID, and about half as fast.

    The key point to consider is why you want speed. If it is for complex video work, SCSI is the fastest solution. If it is to pep up your system, try IDE RAID. If you want to trade a little speed for portability and ease of use, go FireWire.

    For more, read through www.macgurus.com. They have level headed hardware shopping advice, the likes of which you can't find anywhere else!
     
  3. krossfyter thread starter macrumors 601

    krossfyter

    Joined:
    Jan 13, 2002
    Location:
    secret city
    #3
    thank you nipsy.

    so that sounds pretty logical and credible. is there anyone out there that disagrees with what was stated? if so speak out.


    edjemuhcation is fun!
     
  4. Choppaface macrumors 65816

    Joined:
    Jan 22, 2002
    Location:
    SFBA
    #4
    another thing I remember reading was that scsi drives would do ok working on their side, while ata drives would always have to be flat. I think somebody mentioned this when there was that discussion of putting G4s on racks sideways
     
  5. LethalWolfe macrumors G3

    LethalWolfe

    Joined:
    Jan 11, 2002
    Location:
    Los Angeles
    #5
    Right now Firewire drives are just IDE HDDs coupled w/a Firewire I/O. Curren FW drives should be seen as exterior, portable, hot-swapable IDE drives, not "SCSI killers" or anything like that.

    Lethal
     
  6. cb911 macrumors 601

    cb911

    Joined:
    Mar 12, 2002
    Location:
    BrisVegas, Australia
    #6
    so SCSI is still the king??

    eh, for how long?
     
  7. Nipsy macrumors 65816

    Nipsy

    Joined:
    Jan 19, 2002
    #7
    I would say SCSI will stay on top of Enterprise storage until an entirely new protocol surpasses it in perfomance & reliability. IDE drives are often warranted for 1 or 3 years, SCSI for 5. SCSI drives reach rotational speeds of 15k RPM, IDE 7200. SCSI drives reach higher per drive transfer speeds than IDE. IDE runs 2 drives per channel, SCSI 15.

    As mentioned above, there really aren't native FireWire drives. They are IDE drives bridged in FireWire enclosures.

    FibreChannel is making some inroads, but hosts still price themselves for the high-end pro/server market.

    The thing with SCSI is that it has evolved for a very long time, to become the most stable and robust mass storage solution.

    Even IDE RAID boxes bridge to SCSI for communication with the host, because their caches can accommodate SCSI's concurrent requests.

    FireWire (and the proposed FireWire 2) can't beat SCSI for speed when used in RAID environments. IDE can't bet SCSI for speed in smaller (video) environments. Four IDE drives that operate at 50MB/s can compare with the 15 SCSI devices which can be RAIDed on each UW+ channel.

    So, FibreChannel may make headway, but it'll be a long time before SCSI goes the way of the Dodo.
     
  8. AlphaTech macrumors 601

    AlphaTech

    Joined:
    Oct 4, 2001
    Location:
    Natick, MA
    #8
    Not true.

    The reason for not putting the tower on it's side is the optical drive. Hard drives, ATA and SCSI, have no issue with being either horizontal or vertical. You do want both drive types to be either flat or 90°, putting them on any other angle causes the spindle to spin badly, and can cause the drive to fail.

    I have both ATA and SCSI hard drives. The new ATA100/133 drives perform almost as fast as their SCSI cousins. The only drives faster then the ATA133 drives, are the new Ultra160 drives.

    SCSI drives (in my opinion) should only be used where you need very high drive speed (both rpm and transfer rates) such as for video editing and top end animation work. Even there, the current generation of ATA drives provide enough speed to get the job done.

    I have an ATA RAID card inside my game peecee, which accepts up to 4 drives, and has a transfer rate of 266MB/sec (dual channel, with a drive on each set to RAID 0). They do make ATA RAID cards with even more channels, and they do not cost as much as SCSI RAID cards.

    For external drives, you need to decide which is more important to you, portability, or loud, [potentially] fast drives. SCSI drives are loud, no matter where you place them, where there are ATA drives that are (for all practical purposes) silent. You can also pick up external FireWire drives that use the 2.5" form factor and are bus powered. With those, all you need is the FireWire cable (6 pin on both ends), and you are good to go. Trying to connect external SCSI drives to a portable can present more problems. For one thing, you don't have any SCSI ports (at least on the newer PowerBooks and iBooks), adding SCSI can be expensive no matter what method you use, and it won't be as fast as internal drives.

    Currently, FireWire caps out at 400Mbps (50MB/second) and is limited by the chip used for the drives/devices. When FireWire 2 comes out, those speeds will be increased (no one really knows to what level, yet).

    It all boils down to what you like better, money in your wallet, and gobs of storage, or less storage and money. SCSI drives are still more expensive then larger ATA133 drives of much greater size. Compare the price of a new 73GB SCSI drive to an ATA100/133 drive. You can get a brand new ATA133, 160GB drive for under $300, what size SCSI drive can you get for that much??? Don't forget, you can plug ATA drives right into your Mac as soon as you get home with it/them. For SCSI, you will need to get a card, and then the drives are limited by that as well. If you get an Ultra160 drive, but only an Ultra2Wide SCSI card, you are capping yourself with the card (to 80MBps).
     
  9. Catfish_Man macrumors 68030

    Catfish_Man

    Joined:
    Sep 13, 2001
    Location:
    Portland, OR
    #9
    SCSI vs. FireWire

    SCSI advantages:
    up to 320MB/sec transfer (really new, most high end SCSI is still 160MB/sec, built in old mac SCSI is 50MB/sec)

    SCSI disadvantages:
    Expensive
    Massive cables
    Setup hassles
    termination
    only 7 devices on a controller
    non-powered

    FireWire advantages:
    cheaper
    less hassle
    smaller cables
    powered
    can daisy chain more than 7 devices (I think)

    FireWire disadvantages:
    50MB/sec transfer rate (FW2 will be 100MB/sec)
     
  10. alex_ant macrumors 68020

    alex_ant

    Joined:
    Feb 5, 2002
    Location:
    All up in your bidness
    #10
    Both FibreChannel and Firewire ARE SCSI. So SCSI definitely isn't going anywhere...
     
  11. krossfyter thread starter macrumors 601

    krossfyter

    Joined:
    Jan 13, 2002
    Location:
    secret city
    #11
    thanks guys lots of good info... i knew i could trust the macrumors folks.

    alpha or whoever....

    what do you think about the new western
    digital drive that has 8MB of cache on it? i think
    it has close to scsi speeds and at much less of a price...

    whats 411 on this? how does it compare to ATA or whatever else?
     
  12. AlphaTech macrumors 601

    AlphaTech

    Joined:
    Oct 4, 2001
    Location:
    Natick, MA
    #12
    Maybe out in MN they are, but the truth is that they are different technologies. Just as ATA is different then SCSI, so is FireWire.

    The only [current] way to get faster then 160MBps transfer rates is with multi-channel SCSI cards (RAID 0). Otherwise, you max out at either 160MBps, or the max transfer rate of your SCSI card.

    BTW, those high end SCSI cards, and drives, that can run at 160MBps and better, are NOT cheap.

    As for the wd drives, I haven't used any of them. I'd suggest checking some magazines for reviews on them.
     
  13. shadowfax0 macrumors 6502

    Joined:
    May 2, 2002
    #13
    There was big discussion of this fact on slashdot when the Xserve was released, people said "It will never make headway because it doesn't use SCSI..." So we'll have to see, being that it beat out other servers that had SCSI, it seems that they have made up for the couple hundred RPMs of difference somewhere along the way.
     
  14. LethalWolfe macrumors G3

    LethalWolfe

    Joined:
    Jan 11, 2002
    Location:
    Los Angeles
    #14

    In regards to miniDV editing I agree, but if you any do "uncompressed" work (analog or digital source footage) then you have to go SCSI 'cause IDE drives will just choke and drop more frames than a quadriplegic juggler.

    Lethal
     
  15. Nipsy macrumors 65816

    Nipsy

    Joined:
    Jan 19, 2002
    #15

    No, neither interface is SCSI.

    From whatis.com:

    Fibre Channel is a technology for transmitting data between computer devices at a data rate of up to 1 Gbps, or one billion bits per second. (A data rate of 10 Gbps has been proposed by the Fibre Channel Industry Association.) Fibre Channel is especially suited for connecting computer servers to shared storage devices and for interconnecting storage controllers and drives. Since Fibre Channel is three times as fast, it has begun to replace the Small Computer System Interface (SCSI) as the transmission interface between servers and clustered storage devices. Fibre channel is more flexible; devices can be as far as ten kilometers (about six miles) apart if optical fiber is used as the physical medium. Optical fiber is not required for shorter distances, however, because Fibre Channel also works using coaxial cable and ordinary telephone twisted pair.

    Fibre Channel offers point-to-point, switched, and loop interfaces. It is designed to interoperate with SCSI, the Internet Protocol (IP) and other protocols, but has been criticized for its lack of compatibility - primarily because (like in the early days of SCSI technology) manufacturers sometimes interpret specifications differently and vary their implementations.

    Standards for Fibre Channel are specified by the Fibre Channel Physical and Signalling standard, and the ANSI X3.230-1994, which is also ISO 14165-1.


    IEEE 1394, High Performance Serial Bus, is an electronics standard for connecting devices to your personal computer. IEEE 1394 provides a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400 Mbps (megabits per second). The standard describes a serial bus or pathway between one or more peripheral devices and your computer's microprocessor. Many peripheral devices now come equipped to meet IEEE 1394. Two popular implementations of IEEE 1394 are Apple's FireWire and Sony's i.LINK. IEEE 1394 implementations provide:

    * A simple common plug-in serial connector on the back of your computer and on many different types of peripheral devices
    * A thin serial cable rather than the thicker parallel cable you now use to your printer, for example
    * A very high-speed rate of data transfer that will accommodate multimedia applications (100 and 200 megabits per second today; with much higher rates later)
    * Hot-plug and Plug and Play capability without disrupting your computer
    * The ability to chain devices together in a number of different ways without terminators or complicated set-up requirements

    In time, IEEE 1394 implementations are expected to replace and consolidate today's serial and parallel interfaces, including Centronics parallel, RS-232C, and Small Computer System Interface (SCSI). The first products to be introduced with FireWire include digital cameras, digital video disks (DVDs), digital video tapes, digital camcorders, and music systems. Because IEEE 1394 is a peer-to-peer interface, one camcorder can dub to another without being plugged into a computer. With a computer equipped with the socket and bus capability, any device (for example, a video camera) can be plugged in while the computer is running.
    Briefly How It Works
    There are two levels of interface in IEEE 1394, one for the backplane bus within the computer and another for the point-to-point interface between device and computer on the serial cable. A simple bridge connects the two environments. The backplane bus supports 12.5, 25, or 50 megabits per second data transfer. The cable interface supports 100, 200, or 400 megabits per second. Each of these interfaces can handle any of the possible data rates and change from one to another as needed.

    The serial bus functions as though devices were in slots within the computer sharing a common memory space. A 64-bit device address allows a great deal of flexibility in configuring devices in chains and trees from a single socket.

    IEEE 1394 provides two types of data transfer: asynchronous and isochronous. Asynchronous is for traditional load-and-store applications where data transfer can be initiated and an application interrupted as a given length of data arrives in a buffer. Isochronous data transfer ensures that data flows at a pre-set rate so that an application can handle it in a timed way. For multimedia applications, this kind of data transfer reduces the need for buffering and helps ensure a continuous presentation for the viewer.

    The 1394 standard requires that a device be within 4.5 meters of the bus socket. Up to 16 devices can be connected in a single chain, each with the 4.5 meter maximum (before signal attenuation begins to occur) so theoretically you could have a device as far away as 72 meters from the computer.

    Another new approach to connecting devices, the Universal Serial Bus (USB), provides the same "hot plug" capability as the 1394 standard. It's a less expensive technology but data transfer is limited to 12 Mbps (million bits per second). Small Computer System Interface offers a high data transfer rate (up to 40 megabytes per second) but requires address preassignment and a device terminator on the last device in a chain. FireWire can work with the latest internal computer bus standard, Peripheral Component Interconnect (PCI), but higher data transfer rates may require special design considerations to minimize undesired buffering for transfer rate mismatches.
     
  16. Choppaface macrumors 65816

    Joined:
    Jan 22, 2002
    Location:
    SFBA
    #16
    I've got one in my PC (100gb), and it seems that read operations similar to ones done on my mac (G4 with a 15,000 rpm 18gb cheetah) are just as quick. you might want to read this:
    http://barefeats.com/hard22.html
     

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