Path: utzoo!attcan!uunet!ginosko!usc!ucsd!ucbvax!hplabs!hpfcdc!steve From: steve@hpfcdc.HP.COM (Steve Taylor) Newsgroups: comp.sys.hp Subject: Re: Un-partitioning Hard Disk on HP 9000/300 Series Message-ID: <5570273@hpfcdc.HP.COM> Date: 19 Aug 89 01:08:56 GMT References: <1989Aug18.014354.189@cs.rochester.edu> Organization: HP Ft. Collins, Co. Lines: 44 } > While we're on the subject of disks, I see that BASIC 5 now supports a } > Hierarchical File System. How much overhead does this consume on the disk? } As I recall, it requires 512 bytes per [BASIC-type] file. } > And does it eliminate the requirement that files be stored on contiguous } > blocks? } I think so. From "Installing and Maintaining the BASIC 5.0/5.1 System", p2-6: (adapted slightly) Disc Size Approx. Overhead 270K floppy 44% 640K floppy 22% 720K floppy 18% 55M hard disk 6% 130M hard disk 6% Of course, this doesn't include the size you're interested in, but the trend is clear. The 512 bytes per file applies to typed files. 5.0 also added an "untyped" data file which does not have this header. Yes, it eliminates the requirement that files be contiguous. Some other considerations (from p2-5 of the above reference): Feature: HFS: LIF: Directory Hierarchical Single directory structure (multi-directory) on each volume structure Multiple systems HP-UX, BASIC, and BASIC and Pascal can on same volume Pascal systems can share a disk share a disk Extensible files Files are extensible File length is fixed (when a file would otherwise overflow, the system automatically adds space to it) Access times Generally slower Generally faster than LIF than HFS TRANSFER Not implemented as True background process a background process and high data rates Overhead required Requires more Requires less overhead overhead than LIF than HFS