[TheRealPomax]

No thanks: the registry is a truly huge simple key/value store, which is something files-in-dirs are terrible for because almost every single one of them would take up a full block on disk instead of the fraction of a block they actually need.

A better solution would be a simple database (like sqlite3) but then the immediate counter-argument is "okay, so we're done: it's already a simple database", because the registry hive is literally a file-backed database in the same vein as sqlite =)

[rwmj]

The Windows registry is not a "simple key/value store" by a long shot. It is hierarchical, there are many different types of value, and there's a complex system of security attributes. These are simple facts.

You're right that a file per value would take a whole block on disk given the way some filesystems are currently implemented, but that's not an immutable feature of all filesystems - some Unix filesystems store small files in the inode. A real database is possible, but also the registry must be available very early in Windows boot (actually it's used by the bootloader, but also by the critical device database) so you'd want something that's at least easy to read with a smallish amount of code.

[tenebrisalietum]

I feel this mattered much more in the mid 90's when 4GB disks were common in PCs, but with today's modern storage sizes this is trivial. Besides, the NTFS MFT already stores small files directly in the indexes.

[TeMPOraL]

> with today's modern storage sizes this is trivial

And, because almost every vendor thinks like that, median computers of today offer worse UX than their 90's equivalents.