hfs-user March 2002

hfs-user@lists.mars.org

11 participants
18 discussions

Difference in Data types??
by Biswaroop(External) 02 Apr '02

02 Apr '02

HI, Everybody Wishing u all a very Happy Holi.( An Indian festival played with colours) Well in the MDB structure for an HFS volume the field vol.drXTClpSiz /* clump size for extents overflow file */ is 4 bytes long. Again in the Catalog Data Record structure the member filClpSize; /* file clump size */ takes 2 bytes. Therefore when i assign the value of the first variable to the second I lose information. But then one way is to make the MDB's variable contain a value only for 2 bytes then assignment won't make a data loss. But the value for the MDB's variable was calculated as 1/128 th part of the Total volume size. An emphirical formula used in the hfsutils package. Any comments on this??? Please is there any simple formula to find out the extent file size and the catalog file size for a volume when we know before hand how many files have to be in that volume. For eg. if i know i have to write "X" files contained in "Y" number of directories. Then can i calculate what should be the volume's clump size for the extents overflow file and the catalog file. Waiting for ur explanations. Bye Biswaroop Each Day gives us an Opprutunity to Ruin it, those who Fail, Succeed in Life. -- Bisban

4 3

Date Offset
by Entwicklung 28 Mar '02

28 Mar '02

Hello Listers, I've calculated the date and time offset between 1904, Jan 1 midnight and 1970 as : time_t offset = (365*66 + 17 ) *24*3600 1. I'd just like to know if my calculations are ok. The 17 accounts for the extra day in the 17 leap years which occur in this interval. 2. I gathered that Mac uses GMT and the standard C-library time.h bases its calculations on UTC. Would this create any further offset to what I'm considering right now ? If so what would it be ? 3. I also gathered that HFS uses local time and HFS plus uses GMT. Would it be a mistake to save up HFS dates as GMT ? In what way could this create problems ? Could anybody who knows more about this please help me out ?.. would be grateful for any tips / suggestions. Regards, Nandini Hengen

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unsubsribe
by Emmanuel Pagnacco 28 Mar '02

28 Mar '02

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Restrictions on root/index nodes ???
by Entwicklung 27 Mar '02

27 Mar '02

Hello listers, I've encountered a problem which I am not able to attribute to anything particular and would like to know if I am making any basic mistake or have overlooked something. I'm creating a catalog B-Tree with 1 root node (index) containing five ptr recs to a second level of five index nodes, each of which contains 11 pointer records to 11 leaf nodes each. The problem I'm facing is that the files referenced by the last 22 ptr recs i.e. in the last 2 lower level index nodes are not readable on my Mac although the correct Icons do appear and all my files are displayed. I think there must be some problem with the referencing (data fork locations in the leaf nodes) so I checked this but it seems to be fine (just like it is for the first 3 index nodes which work perfectly) . Since all the icons get displayed correctly I thought the problem must lie within the leaf nodes but this doesn't seem to be the case. On my Mac I get an error of the form "Schreib/Lese Fehler" or "Read/Write error"..... What could this be due to ? Checking with hfsutils under Linux gives me the error "Wrong logical location" or similar.... does anybody know what this is due to? I think it must be some basic mistake I am making (related to the HFS-Specifications perhaps ?) but I have been unable to narrow it down so far..(hlp!).. would be glad of some professional advice. Regards, Nandini Hengen

3 3

Mac Error Codes
by Entwicklung 26 Mar '02

26 Mar '02

Hi, I remember I had asked the list a long time back if anyone knew where to find a list of Mac error codes. I found them and the link is: http://www.cbcu.cam.ac.uk/gds/errorcodes.htm for anyone else who needs it too. - Nandini

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Restrictions on root/index nodes ???
by Entwicklung 26 Mar '02

26 Mar '02

Hello listers, This is wrt my previous email to the list.... I just noted that if I try copying files over from my CD to my desktop (i.e. those files which I could open and read initially from my CD ) I get the error - The file 'xyz.txt' can't be read since a read/write error has occured - Do you wish to proceed ? And when I say yes it doesn't get copied anyway (as expected ). Does anyone have an inkling as to what this could be due to ? I'm probably missing out on something basic here and need to proceed... any suggestions/tips would be greatly appreciated. Regards, Nandini Hengen

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Clarification needed wrt B/B*-Trees
by Entwicklung 26 Mar '02

26 Mar '02

Hello listers, The technical notes for HFS+ TN1150 refers to 'B-Trees' and the documentation for HFS in 'Inside Macintosh - Data Organisation on volumes' refers to 'B*- Trees' Going by the definitions provided by NIST (the national institute of standards) a B-Tree is defined as Definition: A balanced search tree in which every node has between t-1 and 2t-1 children, where t is an arbitrary constant. This is a good structure if much of the tree is in slow memory (disk), since the height, and hence the number of accesses, can be kept small, say one or two, by picking a large t. and a B*-Tree is defined as : Definition: A B-tree in which nodes are kept 2/3 full by redistributing keys to fill two child nodes, then splitting them into three nodes. As far as I can gather from the definitions and the documentation, HFS uses a B*-Tree and HFS+ uses a B-Tree.... does anybody know why ? Does this mean that in case of HFS I would have to perform an additional redistribution of keys to keep the nodes just 2/3 full ( which I am not considering right now ) ? The HFS-Specs as such do not mention anything about keeping the nodes just 2/3 full ...or am I wrong there ? Would be glad to hear your comments/feedback ... Regards, Nandini Hengen

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Mkhybrid application and HFS image
by Biswaroop Banerjee 20 Mar '02

20 Mar '02

Hi, Can anybody tell me whether the image file created by the mkhybrid premastering application on Linux dumps the files 2 times i.e. once for the ISO and then for the HFS. or they dump the file contents only once and provide ISO view and HFS view for the same. If not?? then is it possible how to do it?? Again, can anybody give me a link to shareware programs on Windows which will create HFS image from Windows selected files. regards Biswaroop

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Re: [hfs-user] Mapping of filename-extensions
by Entwicklung 20 Mar '02

20 Mar '02

Thanks a ton ! That's exactly what I needed. Regards, Nandini Hengen ----- Original Message ----- From: "Chris Harwell" <charwell(a)digitalpulp.com> To: "Entwicklung" <entwicklung(a)whengenibk.de> Sent: Wednesday, March 20, 2002 4:23 PM Subject: Re: [hfs-user] Mapping of filename-extensions > On Wed, 20 Mar 2002, Entwicklung wrote: > > > Hello everybody, > > I'm looking for some kind of exhaustive list which maps filename extensions onto creator and filetype for MacOS ...say files with extension ".pdf" could be mapped on to a default filetype "PDF " and default creator "CARO" (4-byte values). > > > > I could get hold of these mappings using a freeware tool and a bit of reverse-engineering but I'd rather stick to a standard mapping if anything like that is available. Somebody had told me I could retrieve this info from a Sytem-file on my iMac but I was unable to open this file and view its contents. > > Would be grateful to anyone who knows something about this and can help me out. > > > > Regards, > > Nandini Hengen > hello, > > this list is from the netatalk distribution - seems similar to what your > looking for. i got it from http://sourceforge.net/projects/netatalk/ > > -- > chris > charwell(a)digitalpulp.com >

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Mapping of filename-extensions
by Entwicklung 20 Mar '02

20 Mar '02

Hello everybody, I'm looking for some kind of exhaustive list which maps filename extensions onto creator and filetype for MacOS ...say files with extension ".pdf" could be mapped on to a default filetype "PDF " and default creator "CARO" (4-byte values). I could get hold of these mappings using a freeware tool and a bit of reverse-engineering but I'd rather stick to a standard mapping if anything like that is available. Somebody had told me I could retrieve this info from a Sytem-file on my iMac but I was unable to open this file and view its contents. Would be grateful to anyone who knows something about this and can help me out. Regards, Nandini Hengen

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hfs-user March 2002