Probing EDD (edd=off to disable)

安裝好的 RHEL 6.5 x86-64 系統可以看到 GRUB 但開機後卻停在

Probing EDD (edd=off to disable) 

一直沒有反應,上網查才知道 edd 是 BIOS Enhanced Disk Device Services ,還沒有時間搞定這個是什麼,只知道在 Linux 下參數 edd=off 就可以開機了.

BIOS Enhanced Disk Drive Services (EDD)
參考 http://t13.org/Documents/UploadedDocuments/project/d1386r0-EDD.pdf 的 Introduction 說明.
In the past, DOS has accessed its mass storage devices using a BIOS provided INT 13 interface. This interface
was designed in the early 1980’s and upgraded in the late 1980’s. The maximum theoretical capacity of this API
is 8.4 giga-bytes.
This INT 13 interface, now known as the legacy INT 13 interface, uses function numbers 1-15h and is Cylinder-Head-Sector (CHS) oriented. An extended INT 13 interface has been created, the purpose of these Int 13h extensions is to:

• Replace CHS addressing with Logical Block Addressing (LBA).
• Remove the current requirement of using interrupt 41h/46h to point at the Fixed Disk Parameter Table information.
• Give the BIOS better control over how this data is used.
• Make location and configuration information available to operating systems that do not use the BIOS to access mass storage devices.

主要是開機磁碟的資訊會由 BIOS 提供給 作業系統.