View Full Version : Simple Question

02-11-2001, 03:39 PM
After building many computers with several different OS, I have yet to ever upgrade/replace a harddrive in a Mac. The only question I have is about how to get the harddrives info to the mainboard so the rest of the system will know about the harddrive (cylinder, sectors, heads, ect). From what I can tell, the information is detected everytime at boot, so it is a matter of bolting in the drive and plugging in the cables, then dealing with instilation or restoration of information and the OS.

I am assuming this will be for an IDE or EIDE drive, so no need of SCSI card bios info. In short the question is, is the setup of the drive to the rest of the computer plug n play (autodetect), and if not, where are the setting for the harddrive entered.

If you require clarification, shoot me an email <matth@tidepool.com> or reply to this post.

I do plan on udgradeing to a larger drive for an imac, but was also asked this question in an interview.

Thanks in advance for any information.

02-11-2001, 04:06 PM
The OS never needs to know this (per se). Initialization handles the "recognition" factor by installing a driver and partition map. There are apps out there that can extract that info out of a drive, but why you would need it is beyond me. Besides, with the WWW out there, just log onto the manufacturer's website and look up the drive. What kind of interview was asking you this info? Basically, any IDE drive will "bolt" into an iMac and work, as long as you have it initialized with SW that works with the drive. Apple's DriveSetup will get you a good head start down that road.

02-11-2001, 04:27 PM
The job was for an IT possition at a school district that uses a combination of Mac, Windows NT and Novel. The question they asked was "Discribe the steps in the replment of a harddrive in a Mac, and how is this different from Windows type computers". In windows, You usaly have to give the BIOS information about the rest of the hardware so it knows were it is and how to deal with it. For a harddrive, you need to tell the BIOS about the physical properties of the drive, or you risk problems like out of bounds errors ect. Their is another option in the BIOS (Windows Based Computers) to auto-detect everytime on boot. It sounds like this is simular to what the Mac OS is doing.

Thank you for the reply, I am still learning the Mac hardware and am mainly a network type.

02-11-2001, 04:43 PM
Oh, I gotcha. The Mac OS does what needs to be done without much user interface. In order for you to replace a drive in a Mac, you need to plug it in after setting the jumpers on the drive. This is about all the setup you have to do. In SCSI, it includes termiantion and ID; In ATA it deals with Slave/Master. Then you would boot off of a CD, initilize, and install your OS.

To add in a drive, the steps are the same, except you can boot normally and then use the utility (of your choice) CD/app to initialize the drive and it's there automatically. I don't even know if the OS cares about drive cylinders and all that. Someone with a much deeper OS knowledge will have to tell you all that. I have been upgrading Macs for a more than a dozen years, and have worked on Win, UNIX and Linux a bit. All I can say is thank God for Apple and its simplicity.

02-11-2001, 05:45 PM
So you could say installing a drive in a Mac is the same as a Winodws sytem but a hell-of-a-lot more efficient. Apple's drive setup works with about 90% of the drives out there in my experience. If you have a system that can handle multiple drives (IDE/ATA or SCSI or a mix) then it is even easier as you can make the new drive your main and the old drive your backup.

I will second that Dogstarman!

I'm thinking about getting a Windows system in the next 3 months - if everything goes well (money wise). I hope it wont be to much of a hassle, but I'm going from working with NT (OR trying to) to working Windows '9x/ME with a Novell Network - so I will probably need an x86 to play with. Luckly they do have a few macs to support!

02-11-2001, 06:18 PM
Thanks for the good info. That is what I though, just wanted to make sure.

To extend the discusion...Has anyone tryed ghosting a mac OS form one hard drive to another with Norton Ghost. When I do replace the HD in my imac with a larger one, am I better off trying one of those change your IDE to external USB type boxes, then tranfering over what I need. I was thinking about using one of my Windows boxes to Ghost the drive over, but was unsure about possable file struchture problems. (floopy boot up only of cousre, I am not implying that I will try to boot a mac OS in a windows box, just use the two IDE buses for the transfer) I realize I might be pushing it with this idea, but thought it might work.

02-11-2001, 07:49 PM
Wow. Good question. Never used Ghost before. I would assume if you have the iMac open you will find the IDE ribbon and you should be able to disconnect the CD drive and plug in both HD's temporarily to transfer files. This is a bit of open-case madness, which might no be a great idea for everyone to try. An external box should do the trick. The Windows issue, I will leave to someone else. Not sure at all about that technique.

02-12-2001, 04:22 PM
I have used Ghost a lot whilst I was a PC guy. With the Macs, you could do one of two things:

If copying the boot(primary) drive, just plug in the new drive, and copy. Boot to CD if you are paranoid.

If you copying a non-boot drive, are using EIDE and all 4 drive positions are used up, you could temporarily remove the boot disk, install new disk, boot to CD and copy. Ghost and products like it are unneccessary in the Mac world.

For Novell folks, there is a Server Ghost product that is a big time saver.

02-12-2001, 05:41 PM
careful, Tim. The iMac has just one IDE bus. DogSM's idea to pull the CD makes a lot of sense. It's a hack, but I've done it. I'm a fan of Finder copies as opposed to backing up to tape and then restoring.