Comments for Michael Richmond http://www.smallersystems.com/blog Just another random blog... Tue, 28 Feb 2012 04:22:04 +0000 hourly 1 http://wordpress.org/?v=3.3.1 Comment on How does LTFS work? by Michael http://www.smallersystems.com/blog/2011/06/how-does-ltfs-work/#comment-239 Michael Tue, 28 Feb 2012 04:22:04 +0000 http://www.smallersystems.com/blog/?p=343#comment-239 I worked directly with HP during the LTFS development. I know that the HP version of LTFS for OS X is a copy of the LTFS codebase I developed at IBM and released as open-source with the addition of code to replace the tape operations code with code specific for the HP drive. That is, the filesystem operations and interaction with MacFUSE remain the same between both IBM and HP versions. I have worked with the MacFUSE 2.2 code from Tuxera and have still seen intermittent problems with that version of MacFUSE. I worked directly with HP during the LTFS development. I know that the HP version of LTFS for OS X is a copy of the LTFS codebase I developed at IBM and released as open-source with the addition of code to replace the tape operations code with code specific for the HP drive. That is, the filesystem operations and interaction with MacFUSE remain the same between both IBM and HP versions.

I have worked with the MacFUSE 2.2 code from Tuxera and have still seen intermittent problems with that version of MacFUSE.

]]> Comment on How does LTFS work? by Matt Cunningham http://www.smallersystems.com/blog/2011/06/how-does-ltfs-work/#comment-238 Matt Cunningham Tue, 28 Feb 2012 03:39:26 +0000 http://www.smallersystems.com/blog/?p=343#comment-238 I haven't found anything out of spec, I'm using the HP LTFS binaries and they specify 10.6 (32bit mode) as a compatible OS with MacFUSE 2.0.3,2. They also specify 10.6 (64bit mode) might work with MacFUSE 2.2 from Tuxera. I know you wrote the IBM implementation - is your software hard coded to only work with IBM drives? I haven’t found anything out of spec, I’m using the HP LTFS binaries and they specify 10.6 (32bit mode) as a compatible OS with MacFUSE 2.0.3,2.
They also specify 10.6 (64bit mode) might work with MacFUSE 2.2 from Tuxera.
I know you wrote the IBM implementation – is your software hard coded to only work with IBM drives?

]]> Comment on How does LTFS work? by Michael http://www.smallersystems.com/blog/2011/06/how-does-ltfs-work/#comment-237 Michael Tue, 28 Feb 2012 03:26:43 +0000 http://www.smallersystems.com/blog/?p=343#comment-237 Thanks Matt. As dev lead and architect for the Linux, OS X, and Windows releases; author of the OS X implementation; and a primary author of the LTFS Format Specification, I know a fair bit about LTFS inside and out. Did you identify the cause of your copy problem? I know that we tested LTFS for OS X for well over 6000 files on a tape. However you are using OS X 10.6.4. At the time I left IBM, MacFUSE did not officially support Snow Leopard and I have seen some data corruption issues if MacFUSE is used on 10.6.x. As such, LTFS was not supported on OS X versions more recent than 10.5.x. Thanks Matt. As dev lead and architect for the Linux, OS X, and Windows releases; author of the OS X implementation; and a primary author of the LTFS Format Specification, I know a fair bit about LTFS inside and out.

Did you identify the cause of your copy problem? I know that we tested LTFS for OS X for well over 6000 files on a tape. However you are using OS X 10.6.4. At the time I left IBM, MacFUSE did not officially support Snow Leopard and I have seen some data corruption issues if MacFUSE is used on 10.6.x. As such, LTFS was not supported on OS X versions more recent than 10.5.x.

]]> Comment on How does LTFS work? by Matt Cunningham http://www.smallersystems.com/blog/2011/06/how-does-ltfs-work/#comment-236 Matt Cunningham Tue, 28 Feb 2012 01:09:34 +0000 http://www.smallersystems.com/blog/?p=343#comment-236 Sorry Michael, I've just been reading more of your site - you are indeed THE GURU of LTFS. Sorry Michael, I’ve just been reading more of your site – you are indeed THE GURU of LTFS.

]]> Comment on How does LTFS work? by Matt Cunningham http://www.smallersystems.com/blog/2011/06/how-does-ltfs-work/#comment-235 Matt Cunningham Tue, 28 Feb 2012 00:52:59 +0000 http://www.smallersystems.com/blog/?p=343#comment-235 Hi Michael, you seem to have an intricate knowledge of the LTFS filesystem. I have been trying to write an LTFS tape/volume of Avid MXF files (Mac OSX 10.6.4) For performance I consolidate the media files onto an internal HDD before writing to the LTFS volume. I was initially successful with small test copies but now when I copy 900+ MB to the volume I am getting a "disk full" error when I know there is at least another 400MB free on the volume. I have tried both command-line and Finder copies, both get the same result. I have eliminated any illegal characters. It's almost like the filesystem is running out of inodes (if it was a disk filesystem). The files are not unusually small, and it's only about 6000 files. I am now creating a .spareseimage file on the consolidating HDD and plan on writing that to LTFS but I shouldn't have to go to those lengths to create a tape. Thanks Matt Hi Michael, you seem to have an intricate knowledge of the LTFS filesystem.
I have been trying to write an LTFS tape/volume of Avid MXF files (Mac OSX 10.6.4)
For performance I consolidate the media files onto an internal HDD before writing to the LTFS volume.

I was initially successful with small test copies but now when I copy 900+ MB to the volume I am getting a “disk full” error when I know there is at least another 400MB free on the volume.

I have tried both command-line and Finder copies, both get the same result.
I have eliminated any illegal characters.
It’s almost like the filesystem is running out of inodes (if it was a disk filesystem).
The files are not unusually small, and it’s only about 6000 files.

I am now creating a .spareseimage file on the consolidating HDD and plan on writing that to LTFS but I shouldn’t have to go to those lengths to create a tape.

Thanks
Matt

]]> Comment on Problem with video-stream playback in OS X Lion (10.7) by Wandrille http://www.smallersystems.com/blog/2011/08/problem-with-video-stream-playback-in-os-x-lion-10-7/#comment-234 Wandrille Mon, 27 Feb 2012 21:21:09 +0000 http://www.smallersystems.com/blog/?p=591#comment-234 Awesome! Late 2009 iMac 27 inches. Video freezing, audio continuing to play, VNC black screen. This fixes it as far as I can tell Awesome!

Late 2009 iMac 27 inches. Video freezing, audio continuing to play, VNC black screen.

This fixes it as far as I can tell

]]> Comment on Problem with video-stream playback in OS X Lion (10.7) by Maximus http://www.smallersystems.com/blog/2011/08/problem-with-video-stream-playback-in-os-x-lion-10-7/#comment-233 Maximus Fri, 10 Feb 2012 16:32:55 +0000 http://www.smallersystems.com/blog/?p=591#comment-233 Brilliant! fixed my video playback issue on Lion! Brilliant! fixed my video playback issue on Lion!

]]> Comment on Tape? Does anyone care about tape anymore? by IBM and FOX win an Emmy for LTFS - IT Storage 411: Inside Systems Storage by Tony Pearson - IBM Storage Community http://www.smallersystems.com/blog/2011/06/tape-does-anyone-care-about-tape-anymore/#comment-231 IBM and FOX win an Emmy for LTFS - IT Storage 411: Inside Systems Storage by Tony Pearson - IBM Storage Community Mon, 30 Jan 2012 22:01:12 +0000 http://www.smallersystems.com/blog/?p=165#comment-231 [...] able to come up with a working prototype in just four months. Michael discusses this in his posts [Tape? Does anyone care about Tape anymore?"] and [the Emmy goes to... [...] [...] able to come up with a working prototype in just four months. Michael discusses this in his posts [Tape? Does anyone care about Tape anymore?"] and [the Emmy goes to... [...]

]]> Comment on Problem with video-stream playback in OS X Lion (10.7) by leo http://www.smallersystems.com/blog/2011/08/problem-with-video-stream-playback-in-os-x-lion-10-7/#comment-230 leo Fri, 20 Jan 2012 03:45:12 +0000 http://www.smallersystems.com/blog/?p=591#comment-230 That worked! Many thanks! That worked! Many thanks!

]]> Comment on How does LTFS work? by Michael http://www.smallersystems.com/blog/2011/06/how-does-ltfs-work/#comment-228 Michael Tue, 17 Jan 2012 17:33:13 +0000 http://www.smallersystems.com/blog/?p=343#comment-228 In my post I am using the word "track" in a loose sense to indicate data that is written in one direction. According to Wikipedia, "When the first data band is filled (they are actually filled in 3, 1, 0, 2 order across the tape), the head assembly is moved to the second data band and a new set of wraps is written. <strong>The total number of tracks on the tape is (4 data bands) × (11–20 wraps per band) × (8 or 16 tracks per wrap)</strong>." Taking those numbers, 4 data bands * 20 wraps per band = 80 wraps per tape. My statement about the wrap size of 37.5GB is in error. The correct statement is that the Index Partition and the guard wrap decrease available storage by roughly 37.5GB. Since the Index Partition occupies a single wrap and the guard wrap occupies another wrap. The correct math would be 37.5GB divided by 2 wraps = ~18.75GB per wrap. These numbers will vary in real use due to media quality and data compression. In my post I am using the word “track” in a loose sense to indicate data that is written in one direction. According to Wikipedia, “When the first data band is filled (they are actually filled in 3, 1, 0, 2 order across the tape), the head assembly is moved to the second data band and a new set of wraps is written. The total number of tracks on the tape is (4 data bands) × (11–20 wraps per band) × (8 or 16 tracks per wrap).” Taking those numbers, 4 data bands * 20 wraps per band = 80 wraps per tape.

My statement about the wrap size of 37.5GB is in error. The correct statement is that the Index Partition and the guard wrap decrease available storage by roughly 37.5GB. Since the Index Partition occupies a single wrap and the guard wrap occupies another wrap. The correct math would be 37.5GB divided by 2 wraps = ~18.75GB per wrap. These numbers will vary in real use due to media quality and data compression.

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