Commenter Niels wonders when and how the registry was introduced to 16-bit Windows and how much of it carried over to Windows 95.
The 16-bit registry was
extremely simple.
There were just keys, no values.
The only
hive
was HKEY_.
All it was used for was COM objects and file associations.
The registry was stored in the REG.DAT file,
and its maximum size was
64KB.
It is my recollection that the registry was introduced in Windows 3.1, but Niels says it's not in a plain vanilla install, so I guess my memory is faulty.
None of the 16-bit registry code was carried over to Windows 95.
Windows 95 extended the registry into kernel mode,
added support for values and non-string data types,
increased the maximum registry size (though if some people are to be
believed, not by enough),
and added a bunch of other hives, like
added the HKEY_,
HKEY_,
and
the HKEY_,
The old 16-bit registry code was woefully inadequate for
all these new requirements
(especially the kernel mode part),
so it was all thrown out and a brand new registry written.
In the early days of the Windows 95 registry,
the in-memory
signature value
to identify the data structures which represent an open registry key
were the bytes 52 4C 50 59, which
happened to be the ASCII values for the initials of the two programmers
who wrote it.