qdosmsq:fs:qlwa

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qdosmsq:fs:qlwa [2019/08/17 16:31]
norman Split out qwa_rndm from qwa_uchk.
qdosmsq:fs:qlwa [2019/08/22 14:59] (current)
norman A few corrections based on qxltool experiments!
Line 63: Line 63:
 |qwa_name|$0004|DC.W $0004,<​html><​br></​html>​DC.B '​WIN2'​|Disc label| |qwa_name|$0004|DC.W $0004,<​html><​br></​html>​DC.B '​WIN2'​|Disc label|
 |qwa_spr0|$001A|DC.W $0000|Spare| |qwa_spr0|$001A|DC.W $0000|Spare|
-|qwa_uchk|$001C|DC.$EE8C00CE|update check.|+|qwa_rndm|$001C|DC.W $EE8C|format random number.| 
 +|qwa_uchk|$001E|DC.W ​$00CE|update check.|
 |qwa_intl|$0020|DC.W $0000|interleave factor.| |qwa_intl|$0020|DC.W $0000|interleave factor.|
 |qwa_sctg|$0022|DC.W $0004|sectors per group.| |qwa_sctg|$0022|DC.W $0004|sectors per group.|
Line 135: Line 136:
  
 There are not always 65,536 entries in the map - it can be smaller according to the size of the QLWA disc. There are not always 65,536 entries in the map - it can be smaller according to the size of the QLWA disc.
 +
 +Given that only (!) 65536 map entries are allowed, this makes an upper limit on the size of a
 +QXL file. This works out at 255.9 MB which gives an actual maximum size of 255 Mb which results ​
 +in 8 sectors per group.
  
 Each entry in the group has two purposes. The first is to determine where the data is Each entry in the group has two purposes. The first is to determine where the data is
Line 518: Line 523:
 Formatting a QXL.WIN file as a new hard disc is quite a simple process. From a few tests of various sizes of hard disc, I have determined the following process. Each and every sector group in the formatted disc has an entry in the map. Formatting a QXL.WIN file as a new hard disc is quite a simple process. From a few tests of various sizes of hard disc, I have determined the following process. Each and every sector group in the formatted disc has an entry in the map.
  
-   * The size of the disc is used to determine the number of sectors in a group. The minimum appears to be 4 (for a 1 MB  disc) and increases by 1 each time the file gets too big to fit into the maximum of 65,536 map entries.+   * The size of the disc is used to determine the number of sectors in a group. The minimum appears to be 4 (for a 1 MB  disc) and increases by 1 each time the file gets too big to fit into the maximum of 65,536 map entries. ​There is an upper limit of 255 Mb though - otherwise qwa_ngrp will overflow to zero at 256 Mb. (Ask me how I found out!)
    * The number of sectors in each map entry is calculated as the smallest number that fits into a maximum of 65,536 map entries. Roughly it is the larger of 4 or ((SizeInMb / 32) rounded up to the next whole number if not an exact multiple).    * The number of sectors in each map entry is calculated as the smallest number that fits into a maximum of 65,536 map entries. Roughly it is the larger of 4 or ((SizeInMb / 32) rounded up to the next whole number if not an exact multiple).
    * The map is created in memory as a linked list of words, all pointing at the next word. The last one is set to zero.    * The map is created in memory as a linked list of words, all pointing at the next word. The last one is set to zero.
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 //In order to reduce the length of the page, I've created the table with 4 pairs of columns rather than one. This means that there are not 124 lines, only 32. LOL Read across then down.// //In order to reduce the length of the page, I've created the table with 4 pairs of columns rather than one. This means that there are not 124 lines, only 32. LOL Read across then down.//
  
-^   Group Size^   Disc size (Mb)^ ^   Group Size^   Disc size (Mb)^ ^   Group Size^   Disc size (Mb)^ ^   Group Size^   Disc size (Mb)^ +^   Group Size^   Disc size (Mb)^ ^   Group Size^   Disc size (Mb)^ 
-|    4|   128| |    5|   160| |    6|   192| |    7|   ​224| +|    4|   128| |    5|   ​160| ​ 
-|    8|   256| |    9  288| |   ​10| ​  320| |   ​11| ​  352+|    6|   192| |    7|   ​224| 
-|   ​12| ​  384| |   ​13| ​  416| |   ​14| ​  448| |   ​15| ​  480| +|    8|   256| |     ​     |  
-|   ​16| ​  512| |   ​17| ​  544| |   ​18| ​  576| |   ​19| ​  608| + 
-|   ​20| ​  640| |   ​21| ​  672| |   ​22| ​  704| |   ​23| ​  736| + 
-|   ​24| ​  768| |   ​25| ​  800| |   ​26| ​  832| |   ​27| ​  ​864| + 
-|   ​28| ​  896| |   ​29| ​  928| |   ​30| ​  960| |   ​31| ​  ​992| +
-|   ​32| ​ 1024| |   ​33| ​ 1056| |   ​34| ​ 1088| |   ​35| ​ 1120| +
-|   ​36| ​ 1152| |   ​37| ​ 1184| |   ​38| ​ 1216| |   ​39| ​ 1248| +
-|   ​40| ​ 1280| |   ​41| ​ 1312| |   ​42| ​ 1344| |   ​43| ​ 1376| +
-|   ​44| ​ 1408| |   ​45| ​ 1440| |   ​46| ​ 1472| |   ​47| ​ 1504| +
-|   ​48| ​ 1536| |   ​49| ​ 1568| |   ​50| ​ 1600| |   ​51| ​ 1632| +
-|   ​52| ​ 1664| |   ​53| ​ 1696| |   ​54| ​ 1728| |   ​55| ​ 1760| +
-|   ​56| ​ 1792| |   ​57| ​ 1824| |   ​58| ​ 1856| |   ​59| ​ 1888| +
-|   ​60| ​ 1920| |   ​61| ​ 1952| |   ​62| ​ 1984| |   ​63| ​ 2016| +
-|   ​64| ​ 2048| |   ​65| ​ 2080| |   ​66| ​ 2112| |   ​67| ​ 2144| +
-|   ​68| ​ 2176| |   ​69| ​ 2208| |   ​70| ​ 2240| |   ​71| ​ 2272| +
-|   ​72| ​ 2304| |   ​73| ​ 2336| |   ​74| ​ 2368| |   ​75| ​ 2400| +
-|   ​76| ​ 2432| |   ​77| ​ 2464| |   ​78| ​ 2496| |   ​79| ​ 2528| +
-|   ​80| ​ 2560| |   ​81| ​ 2592| |   ​82| ​ 2624| |   ​83| ​ 2656| +
-|   ​84| ​ 2688| |   ​85| ​ 2720| |   ​86| ​ 2752| |   ​87| ​ 2784| +
-|   ​88| ​ 2816| |   ​89| ​ 2848| |   ​90| ​ 2880| |   ​91| ​ 2912| +
-|   ​92| ​ 2944| |   ​93| ​ 2976| |   ​94| ​ 3008| |   ​95| ​ 3040| +
-|   ​96| ​ 3072| |   ​97| ​ 3104| |   ​98| ​ 3136| |   ​99| ​ 3168| +
-|  100|  3200| |  101|  3232| |  102|  3264| |  103|  3296| +
-|  104|  3328| |  105|  3360| |  106|  3392| |  107|  3424| +
-|  108|  3456| |  109|  3488| |  110|  3520| |  111|  3552| +
-|  112|  3584| |  113|  3616| |  114|  3648| |  115|  3680| +
-|  116|  3712| |  117|  3744| |  118|  3776| |  119|  3808| +
-|  120|  3840| |  121|  3872| |  122|  3904| |  123|  3936| +
-|  124|  3968| |  125|  4000| |  126|  4032| |  127|  4064| +
-|  128|  4096| |     ​| ​     | |     ​| ​     | |     ​| ​     | +
  • qdosmsq/fs/qlwa.txt
  • Last modified: 2019/08/22 14:59
  • by norman