Re: [ql-users] Size for QXL.win Files
Nasta writes: If you want to be absolutely sure, 1G QXL.WIN, with 32k allocation block size is the way to go, it avoids all the possible pitfalls... Actually a 1G QXL.WIN drive (cant we find a better name for QXL.WIN files? How about just Win files?) has an allocation block size of 16k; 2G has 32k. As you say, there is some confusion about whether the allocation block counter is signed or not. I think I have read a Win file that was 4G, but QPC2 wont create them. Per ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
Re: [ql-users] Size for QXL.win Files
On 08/07/05 at 11:23 P Witte wrote: John Gilpin writes: 4Gb per QXL.win file... I only get 2GB with QPC2: FORMAT win8_4000 fails while win8_2000 doesnt. Even then the file allocation block is a massive 32k. It seems to me that 4GB must be the theoretical limit for the current mapping scheme. The minimum space taken by a file on disk would then be a whopping 64k Per Per is right, IIRC QLWA may have a 2G limit, even though 4G would be the theoretical maximum. There are two possible reasons for it: 1) Maximum number of allocation blocks (think of them as a sort of super-sector) is a 16 bit word, unfortunately, some implementations and versions took it a s a signed integer instead of unsigned. 2) Maximum size of one allocation block is a 16 bit word, again some implementations and versions used signed arithmetic to point to a byte within the block, which reduces it's maximum size to 32k. IIRC the first error is the more likely to crop up. When QUBIDE was being maintained, these cropped up, but I do not remember the speciffics any more. 4G is a sort of double limit as the system implies that the whole QLWA partition can be used up by a single file. Since the file pointer is a 32 bit unsigned (hopefully!) integer, the maximum size of a file is 4G, and so is the size of the partition (64k blocks each 64k in size = 4G). The serious limitiation here is that one file always takes up at least 1 allocation block (even if the file is empty!) and the less serious one is that there can be max 64k files. The first is quite restrictive in QL terms as files are, in general, much shorter than 64k. This produces a lot of wasted space. If you want to be absolutely sure, 1G QXL.WIN, with 32k allocation block size is the way to go, it avoids all the possible pitfalls... Nasta ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
Re: [ql-users] Size for QXL.win Files
- Original Message - From: ZN [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, July 14, 2005 2:53 PM Subject: Re: [ql-users] Size for QXL.win Files On 08/07/05 at 11:23 P Witte wrote: John Gilpin writes: 4Gb per QXL.win file... I only get 2GB with QPC2: FORMAT win8_4000 fails while win8_2000 doesnt. Even then the file allocation block is a massive 32k. It seems to me that 4GB must be the theoretical limit for the current mapping scheme. The minimum space taken by a file on disk would then be a whopping 64k Per Per is right, IIRC QLWA may have a 2G limit, even though 4G would be the theoretical maximum. There are two possible reasons for it: 1) Maximum number of allocation blocks (think of them as a sort of super-sector) is a 16 bit word, unfortunately, some implementations and versions took it a s a signed integer instead of unsigned. 2) Maximum size of one allocation block is a 16 bit word, again some implementations and versions used signed arithmetic to point to a byte within the block, which reduces it's maximum size to 32k. IIRC the first error is the more likely to crop up. When QUBIDE was being maintained, these cropped up, but I do not remember the speciffics any more. 4G is a sort of double limit as the system implies that the whole QLWA partition can be used up by a single file. Since the file pointer is a 32 bit unsigned (hopefully!) integer, the maximum size of a file is 4G, and so is the size of the partition (64k blocks each 64k in size = 4G). The serious limitiation here is that one file always takes up at least 1 allocation block (even if the file is empty!) and the less serious one is that there can be max 64k files. The first is quite restrictive in QL terms as files are, in general, much shorter than 64k. This produces a lot of wasted space. If you want to be absolutely sure, 1G QXL.WIN, with 32k allocation block size is the way to go, it avoids all the possible pitfalls... Nasta Thanks for the advice, Nasta, and all explained so that I can follow the reasoning. I will do a bit of experimenting but the comments received as to what should be theoretically achievable is a great help. John Gilpin. ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
Re: [ql-users] Size for QXL.win Files
John Gilpin writes: 4Gb per QXL.win file is more than enough for me! I just didn't want to set it all up then find I had overstepped the mark. (I will probably set up three or four 1Gb files and see how it goes. - my BIG Hard drive is about 80Gb in total ). I only get 2GB with QPC2: FORMAT win8_4000 fails while win8_2000 doesnt. Even then the file allocation block is a massive 32k. It seems to me that 4GB must be the theoretical limit for the current mapping scheme. The minimum space taken by a file on disk would then be a whopping 64k Per ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
[ql-users] Size for QXL.win Files
Having installed a large Hard Drive on my PeeCee (on which I run QPC2) I would like to dedicate some storage space for QL files. I understand that the way to do this is to generate one or more QXL.win type files to act as Winchester devices. Is there a maximum size for a QXL.win file running on QPC2 and if so, what is the maximum size allowed? Regards, John Gilpin. ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
Re: [ql-users] Size for QXL.win Files
John Gilpin wrote: Is there a maximum size for a QXL.win file running on QPC2 and if so, what is the maximum size allowed? Actually, I don't know what the maximum size is. I do know that QPC's access routines are currently limited to 4GB per QXL.WIN file, however. It would probably be fairly easy to extend this to 2TB, but I'm not sure how much space the QLWA format itself can handle anyway. Marcel ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
Re: [ql-users] Size for QXL.win Files
Thanks for that, Marcel. 4Gb per QXL.win file is more than enough for me! I just didn't want to set it all up then find I had overstepped the mark. (I will probably set up three or four 1Gb files and see how it goes. - my BIG Hard drive is about 80Gb in total ). Regards, John Gilpin. - Original Message - From: Marcel Kilgus [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, July 07, 2005 10:33 PM Subject: Re: [ql-users] Size for QXL.win Files John Gilpin wrote: Is there a maximum size for a QXL.win file running on QPC2 and if so, what is the maximum size allowed? Actually, I don't know what the maximum size is. I do know that QPC's access routines are currently limited to 4GB per QXL.WIN file, however. It would probably be fairly easy to extend this to 2TB, but I'm not sure how much space the QLWA format itself can handle anyway. Marcel ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
Re: [ql-users] Size for QXL.win Files
In message [EMAIL PROTECTED], John Gilpin [EMAIL PROTECTED] writes Having installed a large Hard Drive on my PeeCee (on which I run QPC2) I would like to dedicate some storage space for QL files. I understand that the way to do this is to generate one or more QXL.win type files to act as Winchester devices. Is there a maximum size for a QXL.win file running on QPC2 and if so, what is the maximum size allowed? I don't know either. I have a 250mb file at the moment and may extend that to 300mb because of all the stuff I have in it. By way of an advert. Creating and using QXL.WIN files is tackled in the new QL Today 'Start Here' article which I have just emailed to Jochen. Expect volume 10 issue 1 to drop onto your doormat in two weeks time. And by way of a reminder to those yet to re-subscribe (or subscribe?) Now is the time if you don't want to miss out. -- Roy Wood Q Branch. 20 Locks Hill, Portslade, Sussex.BN41 2LB Tel: +44 (0) 1273 386030fax: +44 (0) 1273 430501 skype : royqbranch web : www.qbranch.demon.co.uk ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
Re: [ql-users] Size for QXL.win Files
Την Thu, 07 Jul 2005 17:33:36 -0400,ο(η) Marcel Kilgus [EMAIL PROTECTED] έγραψε: John Gilpin wrote: Is there a maximum size for a QXL.win file running on QPC2 and if so, what is the maximum size allowed? Actually, I don't know what the maximum size is. I do know that QPC's access routines are currently limited to 4GB per QXL.WIN file, however. It would probably be fairly easy to extend this to 2TB, but I'm not sure how much space the QLWA format itself can handle anyway. Marcel I've used 1,2 and 4 Gbyte QXL.WIN files with QPC and I found them without problems. I have encountered (From some twist of fate) a lot more problems with 32 Meg size files than with the huge ones Phoebus ___ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
