---------- Forwarded message ---------- Date: Mon, 10 Feb 2003 00:34:33 -0800 From: [EMAIL PROTECTED] To: Robert de Bath <[EMAIL PROTECTED]> Cc: Tom Oehser <[EMAIL PROTECTED]>, [EMAIL PROTECTED] Subject: Re: [tomsrtbt] thoughts on large files
On Sun, Feb 09, 2003 at 11:16:27AM +0000, Robert de Bath wrote: > On Sun, 2 Feb 2003, Tom Oehser wrote: >> Well, I have mentioned before that dd-lfs is the only thing >> on tomsrtbt that can handle files over 2GB. This is fine >> for piping archives to and from a big archive file. But what >> about archiving and restoring when files in the filesystems >> are over 2GB? Short of upgrading to glibc2 or NewLib, or > Just some other warnings about cpio and tar you will need: > 1) The old/standard binary cpio format has a 32 bit file lenght. > 2) The cpio -c format is limited to 8589934591 byte files. > 3) Depending on implementation the tar file format might be > limited to just short of 1TB files or 100GB files. > Obviously the cpio format limit of just over 8GiB isn't enough the > higher tar limit should be enough for a little while but 100GB could > (possibly) be reached for a single file now. > BTW: > Creating or extracting these file needs just two extra system calls > (assuming the kernel copes), the open64() that disables the 2GiB limit > (Just an extra flag IIRC) and the stat64 or llseek call to find the > file length for the header. The 64 bit "long long" type has been > available in GCC since before vsn 1.40 and I believe the *64 syscalls > were added in later libc5 versions. > Do you need anything except tar (pax) to look at big files ? > Later: Okay I've just looked and yes in the kernel's asm/fcntl.h Perhaps a separate (ramdisk installable? or NFS mountable) copy of star (Joerg Schilly's version of tar) would work better for those cases. I don't know, just off hand, how hard it would be to link against Tom's libc5, though. For some cases a Tom's rtbt derivative with just mkfs, ifconfig, mount, and star (lilo can be accessed from the restored system after chroot . /bin/bash) and (what am I forgetting here?) would be enough for a fully automated system restore floppy. I wrote one of those a few years ago. As a practical matter I've moved on to the LNX-BBC somewhat more as a) I'm a minor contributor to the project, b) my wife is more involved, and c) almost all of my machines, and those of my clients, now boot from CDs. (No offense intended Tom; and I still do have two 386s in production at home, so I still need you! <b>) -- Jim Dennis
