紀錄, 記東記西

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負責管理UEFI的UEFI Forum, 就組織分配上, 分成四種work group, 每一個各司其職

UEFI Board -> USWG, PIWG, UTWG, ICWG

當中前兩者, 分別代表的就是UEFI Spec Work Group, 以及PI Group (其他兩個是UEFI Test WG, Industry Communication WG)

USWG又有分三個Sub-team在裏頭, 這邊不再繼續討論.

主要是想從這邊帶出前兩個Work Group分別負責各自的Spec

而各自Spec代表著不同階段的應用.

UEFI作為硬體與軟體之間(ex, OS, diagnostic tools, etc)溝通的韌體介面,

開機的建構階段則交由PI - Platform Iniitialization負責.

故整個UEFI環境是由PI+UEFI所組成.

(Screenshoted from Intel Education Home (https://noggin.intel.com/))
(PDF file: Beyond BIOS - Exploring the Many Dimensions of the Unified Extensible Firmware Interface, p.17)
(Figure 4: PI/UEFI Layering (Source: Intel Corporation, 2011))

這邊圖可以看出整個系統建構中, UEFI跟PI負責的部分

H部分(PI)做好與硬體部分的連結後, 再透過UEFI連接, 就原文敘述:

UEFI Spec is about interfaces between OS, add-in driver and system firmware.

- OSs and other high-level SW should only interact with interfaces and services defined by the UEFI Spec

PI Specs relate to making UEFI implementations

- Promote interoperability between firmware components providers

- All interfaces and services produced and consumed by firmware only

(Screenshoted from UEFI Forum(www.uefi.org))

(Presentations and Video page:  UEFI Plugfest June 22 – 24, 2010 (kind of old document..))

(UEFI Introduction and Welcome (pdf, p6))

換張圖來看, 這邊可以看到再詳細一些的圖解

前一張的Silcon Component Modules, 這邊分別是寫了CPU PEIMs跟Chipset PEIMs

即PI中PEI階段裡使用的Modules

中間原先的Platform Drivers這邊列出了CSM, UEFI drivers, DXE Drivers等等.

接著透過UEFI, 連接支援的OS, preOS環境Shell, 或是OpROM; 另一邊如需要則透過CSM連接Legacy OS.

//自己會有個疑慮, 就圖上註解的年份, 前一張的2011還比後一張的2010新, 但我想闡述的概念是大致相同的, 故不多深入了

換個面向來討論, 以平台開機流程來區分,

UEFI所涵蓋的過程在右半邊, 而左半邊就沒有Cover到; 反之PI則是涵蓋左半邊的開機流程, 右邊則是沒有.

(Screenshoted from Intel Education Home (https://noggin.intel.com/))

(pdf file: Beyond BIOS - Exploring the Many Dimensions of the Unified Extensible Firmware Interface, p.12, 13)

(Figure 1, 2: Where EFI and UEFI Fit into the Platform Boot Flow (Source: Intel Corporation, 2010))