* 仕様書

[REFS[
- [1] [CITE@en[URL Standard]] ([TIME[2016-02-15 18:33:32 +09:00]] 版) <https://url.spec.whatwg.org/#windows-drive-letter>
]REFS]

* 構文

[2] [DFN[[RUBYB[Windowsドライブ文字]@en[Windows drive letter]]]]は、
[[ASCII英字]]とそれに続く [CODE[:]] または [CODE[|]] の2つの[[符号位置]]の列です
[SRC[>>1]]。

[FIG(railroad)[
= [[ASCII英字]]
= |
== [CODE[:]]
== [CODE[|]]
]FIG]

[3] [DFN[[RUBYB[正規化済みWindowsドライブ文字]@en[normalized Windows drive letter]]]]は、
[[Windowsドライブ文字]]のうち、2つ目の[[符号位置]]が [CODE[:]]
であるものです [SRC[>>1]]。

[FIG(railroad)[
= [[ASCII英字]]
= [CODE[:]]
]FIG]

* 歴史

[4] [CITE@en[Editorial: move Windows drive letter to a more logical location]]
([[annevk]]著, [TIME[2017-02-02 21:59:33 +09:00]])
<https://github.com/whatwg/url/commit/ac6489f9b0cf55b27fd1401ab77bc452c97d1457>

[5] [CITE@en[Editorial: move Windows drive letter to a more logical location]]
([[annevk]]著, [TIME[2017-02-02 21:59:33 +09:00]])
<https://github.com/whatwg/url/commit/ac6489f9b0cf55b27fd1401ab77bc452c97d1457>


[6] [CITE[Harald Alvestrand's IETF activities]], [TIME[2025-06-16T10:40:33.000Z]], [TIME[2001-11-17T08:29:29.029Z]] <https://web.archive.org/web/20011117082614/http://www.alvestrand.no/~hta/ietf/>

>
[PRE[
Some words on <a href="../../../../../D%7C/cygwin/home/Administrator/webstuff/ietf/unicode.html">UNICODE/ISO
10646</a></li>
]PRE]