Date: Sun, 19 Oct 2003 09:33:40 -0700 (PDT) From: David Dierlam <[EMAIL PROTECTED]>
---I keep hearing the term "flashing" used a lot here."They flashed a PCI card with 9.2" or something like that. Could somebody spend a minute here and explain what this encompases and why it was necessary. I guess I was absent the day that topic was discussed.(I was out doing my own flashing)Just kidding....
PCI cards which need to be operational before the OS loads from the hard drive, have their drivers (or a subset thereof) stored on the PCI card itself in a piece of non-volatile memory. If you think about it, you can see why this is. The Mac doesn't know what to do with a PCI card if it hasn't loaded a driver for the card. It can't load a driver (extension) until it loads the OS. So, if the card is needed before the OS loads, the Mac must get the driver from somewhere other than and earlier than an extension.
Written into the PCI standard are instructions to have the host computer poll the PCI cards to determine if there are drivers stored on the cards that need loading. This is how the driver can get from storage on the PCI card into the Mac's memory. Details in this paragraph may be wildly inaccurate, but that's the general idea.
Drivers written for the Mac are very different from ones written for a PC or other platform. So a PCI card made for a PC has a PC driver stored on the memory chip on the PCI card. That PC driver won't work on a Mac, anymore than you can substitute PC DLLs for Mac extensions.
Flashing the card involves replacing the driver stored on the card with a different driver. In many instances discussed here, it means replacing a PC driver on a cheaper PC card, with the Mac driver. This works because for many cards the only difference between the Mac and the PC version is the firmware on the card. The hardware is often identical.
In some instances there are software utilities which will write the desired driver to the memory chip on the card, while the card is installed in the computer. This is the process known as "flashing". It is called that, because the rewritable, non-volatile chip is typically a Flash memory chip, although sometimes it is actually an EEPROM, not a Flash.
Sometimes there is only a flashing utility available which runs on the PC. The flashing software is software, so it is also platform specific. In general, one can use a flashing utility to write an contents you wish to the destination card, if you can figure out what it is using as the source data. In practice, there isn't much point in writing, e.g., your 5th grade book report in MacWrite format to a video card's memory chip.
More complex flashing can involve physically removing the memory chip and rewriting it in a chip programming machine--a machine specifically made for programming non-volatile memory chips. One might take this route if no flashing utility is available for the card, or if the flashign utilities are restricted in some way.
More complex conversions require changing or moving components on the PCI card in order to convert the PC hardware to the Mac configuration. So cards are <Miracle Max accent> only mostly identical </Miracle Max accent> and so need some tweeking to convert.
Now days, the firmware (ROM) that makes the computer run is also stored on a rewritable chip, so one can now flash the newer Macs with firmware updates.
Jeff Walther
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