VMWARE ESXi 4.0 Partitions on 1GB Flash drive or Hard Disk

VMWARE ESXi 4.0 contains 5 Partitions.
• Partition 4 enables the actual booting from flash
• Partition 5 contains files that make up the VMware ESXi image (60 MB)
• Partition 6 is used to store a future update to the image file
• Partition 7 is for a core dump
• Partition 8 contains tools, drivers, and the Windows-based vSphere Client installer

Take a look at this blog for details on what each partition contains:
http://www.vcritical.com/2009/08/if-vmware-esxi-4-is-so-small-why-is-it-so-big/