Fedora Core 1.0 (Yarrow) was released on 6th November 2003. Improvements over Red Hat Linux 9 include automated updates with yum, improved laptop support (ACPI, cpufreq) and faster program start time (prelinking).
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YUM is...
Yellow Dog Updater, Modified, yum for short, is a package manager for RPM Package Manager compatible Linux systems.
Its main advantages over the RPM version of the Advanced Packaging Tool apt are
Smaller codebase
Better dependency handling
Yum will likely become the standard tool for updating Red Hat Linux / Fedora Linux.
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Personally I heard about it recently and the Red Hat series is being abandoned for Fedora so go for it.