Gray color installers are machine specific & won't work on you iMac. They were provided by Apple during the tramnsition from Panther to Tiger.
You can upgrade directly to Tiger 10.4 if your iMac meets the Tiger requirements.
Tiger install DVDs are in short supply. Tiger is no longer available from Apple. For other sources, do a Google search for
MA453Z/A (10.4.6),
MA190Z/A (10.4.3) and
M9639Z/A (10.4) . Also look on eBay. Be sure & buy a retail version (black with silver X)
and not a model specific version (gray). Expect to pay (possibly a lot) more than the Apple list price of $129.
Also check this web store
http://www.lacomputercompany.com/cgi-bin/rpcart/index.cgi?command=dispitem&type= sku&sku=19521
Possible Alternative if you are currently using Panther 10.3 – Do a Google search for
Tiger 10.4 Upgrade DVD . It will upgrade your 10.3 to 10.4, but it doesn’t contain the full retail Tiger installer. Should be cheaper than the retail Tiger install DVD.
After you install the base 10.4.x, update to the final Tiger version 10.4.11. Here's the link for the 10.4.11 combo update
http://support.apple.com/kb/TA24901?viewlocale=en_US
Look at this link
Mac OS X v10.4 Tiger Installing Software Support Page
http://www.apple.com/support/tiger/install/
You can also download the
Tiger Installation and Setup Guide
http://manuals.info.apple.com/en/TigerInstall_SetupGuide.pdf
When you upgrade the OS, do it via Archive & Install. See
About the Archive and Install feature
http://support.apple.com/kb/HT1710
Be sure to select Preserve Users & Settings. Also, repair permissions before and after the install.
Cheers, Tom 😉
