Difference between PCI Card and PCI Host Card


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Thread: Difference between PCI Card and PCI Host Card

  1. #1
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    Difference between PCI Card and PCI Host Card

    What is the difference between a PCI Card and a PCI Host Card. Another question: Does one need to have a RAID Controller Card in order to run RAID Software? If not, what's the purpose of having those PCI RAID Controller Cards? For better speed and efficiency? Thanks for any help.

    EVAC

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    I sadly can't answer your first question about the PCI Cards. My assumption would be that the PCI Host Card would be some type of IDE controller for a PCI bus which exists.

    As for the RAID card, you don't need a RAID PCI Card IF you have RAID built onto the motherboard. If it is, then you can run RAID freely. If not, then you'll need a RAID PCI Card. Performance wise I can't tell you because I've never used it, but I've read a few times that the cards seem to perform better overall which doesn't really make sense to me, but it's what I've seen around on some forums.
    The Swain

    dswain

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    You do NOT need a RAID card in order to have a RAID system, even if you don't have one on board. I have a RAID1(mirroring) system on a computer using a PCI-IDE card. You don't even need that, you can run one off of the first and second IDE connections on your mobo(not hda and hdb, but hda and hdc, cause that'll kill all of your performance).

    However, you will have to setup the Linux Software RAID, which is cake to setup, just read the software raid howto.

    Yes, cards do run faster than the software RAID, but it really depends on the usage. If you're a gamer and want to do a striping RAID to run games faster, and the faster the better, then go with a card, or your onboard RAID.
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    Oh I see, my mistake. Very interesting... just a huntch I had that you did. Then what's the point of making a specific RAID-Card or installing it onboard?
    The Swain

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    Originally posted by DSwain
    Oh I see, my mistake. Very interesting... just a huntch I had that you did. Then what's the point of making a specific RAID-Card or installing it onboard?
    Are you talking about the software RAID vs. hardware RAID?
    Hardware RAID will defenantly perform better, since it has it's own processor and not requiring software. Software RAID uses software and the CPU, stealing precious cycles from all them applications you run.

    evac-q8r: When it comes to harddrive controllers, PCI Card and PCI Host Card are the same. They are can also be called Host Adaptors. ie., SCSI Host Adaptor.

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    Originally posted by The Whizzard
    When it comes to harddrive controllers, PCI Card and PCI Host Card are the same. They are can also be called Host Adaptors. ie., SCSI Host Adaptor.
    Yes- not all PCI cards are host cards/adapters; a "host adapter" is a specific type of PCI card, whose function is to act as an interface beween peripheral (usually storage) devices and the computer (the "host").

    For example- cards which allow you to interface external SCSI, Fibre channel, USB, etc. devices via the PCI bus would be considered "host adapters", but something like a PCI modem or video card would be considered a simple "PCI card".

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    Thank you all for clearing up any misunderstandings that I may have previously had. I really appreciate your help.

    EVAC
    Last edited by evac-q8r; 01-21-2005 at 06:19 PM.

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    Glad we could help; that's why we're here, after all...


    (well... that, and the fact that don't have "real" lives. )

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    One other question about the host PCI card. When you say interface do you mean that I could have the input from one device into the host card and output to another device from the host card without any information actually ever having the reach the motherboard to be processed. If I'm right on this stance, in the case the information does reach the motherboard for whatever reason it could be considered as acting as an ordinary PCI card more or less. Is it possible you could give me one simple scenario that one might want to go with this setup? So far the idea is very abstract.

    EVAC

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    Originally posted by evac-q8r
    When you say interface do you mean that I could have the input from one device into the host card and output to another device from the host card without any information actually ever having the reach the motherboard to be processed.

    If I'm right on this stance, in the case the information does reach the motherboard for whatever reason it could be considered as acting as an ordinary PCI card more or less. Is it possible you could give me one simple scenario that one might want to go with this setup? So far the idea is very abstract.

    EVAC
    Ahh... very perceptive, and you are correct about the concept being very abstract.

    I have to get ready for a dinner cruise on the San Francisco bay right now (Yay- a company funded outing by my g/f's employer!), but yes- your question actually delves into lower-level issues such as the technical differentiation between "host adapters" and "host controllers" (among other things). It's an interesting subject; I'll get back to this thread with more info on all of that over the weekend.

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    Originally posted by DMR

    I have to get ready for a dinner cruise on the San Francisco bay right now
    That's cool as long as you bring me back some chicken wings from the cruise. Oh... I guess I should vouch for the others so if you could possibly bring back some wings for tecknophreak, DSwain, and The Whizzard, that'd be great!! Anyways, have fun!!

    EVAC
    Last edited by evac-q8r; 01-22-2005 at 02:37 PM.

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    Wow the last post I saw was about PCI Hosts and PCI Cards, and now wings for everyone? Good little post here...
    The Swain

    dswain

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    Originally posted by evac-q8r
    That's cool as long as you bring me back some chicken wings from the cruise. Oh... I guess I should vouch for the others so if you could possibly bring back some wings for tecknofreak, DSwain, and The Whizzard, that'd be great!! Anyways, have fun!!

    EVAC
    Hey! I'm not a freak, I'm a phreak!! Just clearing it up so some freak doesn't get my wings!! mmmm tommy want wingie.
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  14. #14
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    Sorry folks- they didn't have wings, just Roast Beast and Salmon. There *burp!* wasn't any Beast left over, but I did bring you back a Salmon:







  15. #15
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    Originally posted by evac-q8r
    One other question about the host PCI card. When you say interface do you mean that I could have the input from one device into the host card and output to another device from the host card without any information actually ever having the reach the motherboard to be processed.
    Not quite. At least some communication and transfer of information has to be passed to/from the CPU and system memory, but host controllers usually use a function called "bus mastering" to minimize that overhead. With bus mastering, the host adapter performs many of the functions (that occur during device reads/write operations) which traditionally needed to be initiated and overseen by the CPU. For example, the host controller can write input from a device directly to system memory without having to process it through the CPU first.

    In terms of totally bypassing the motherboard though, host adapters don't have enough "smarts" and computing firepower to perform many of the necessary operations involved in disk I/O, so intervention by the CPU and operating system is required. For example, host adapters are not complex enough to deal with changing/updating the file/folder information for all of the many possible filesystems (NTFS, FAT, FAT32, ext2, ext3, JFS, reiserfs, etc.) that might be being used by devices to which they are writing data; operations like that are the job of the specific operating system being used. There are many other reasons why the host adapter can't entirely act like a separate CPU, but you probably get the idea.



    Originally posted by evac-q8r
    If I'm right on this stance, in the case the information does reach the motherboard for whatever reason it could be considered as acting as an ordinary PCI card more or less.
    Any peripheral device is going to have to interact with the operating system in some way, meaning that the CPU and system RAM will have to be part of the equation. I guess what basically differentiates a host controller or adapter from other types of PCI cards is that its particular function is to act as a translation and communication management agent which allows non-PCI peripheral devices to interact with the host computer and operating system via the PCI bus. That is, of course, a very general and simple description, but I hope it answers your question at somewhat.


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