qdosmsq:fs:qlwa

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
qdosmsq:fs:qlwa [2019/02/21 21:10]
norman Minor corrections to format example.
qdosmsq:fs:qlwa [2021/04/04 13:09] (current)
normandunbar Fixed (!) group versus max file siae table formatting.
Line 21: Line 21:
 |qwa_name|$0004|22 bytes|up to 20 characters, space padded name. Word count first then bytes.| |qwa_name|$0004|22 bytes|up to 20 characters, space padded name. Word count first then bytes.|
 |qwa_spr0|$001A|2 bytes|spare - set to zero.| |qwa_spr0|$001A|2 bytes|spare - set to zero.|
-|qwa_uchk|$001C|long|update check<html><sup>1</sup></html>.|+|qwa_rndm<html><sup>1</sup></html>|$001C|word|format random number.| 
 +|qwa_uchk|$001E|word|update check<html><sup>2</sup></html>.|
 |qwa_intl|$0020|word|interleave factor (0 = SCSI/QXL.WIN).| |qwa_intl|$0020|word|interleave factor (0 = SCSI/QXL.WIN).|
 |qwa_sctg|$0022|word|sectors per group.| |qwa_sctg|$0022|word|sectors per group.|
Line 42: Line 43:
 **Notes:** **Notes:**
  
-1. The update check is incremented by 1 every time a file is created, deleted etc. If you open a file in //over// mode and then close it again without doing anything, this number will increment, this is because you have (just) overwritten the file!+1. This is my own name for this field as, previously, it was undocumented and lumped in with the access counter just as the high word. 
 + 
 +2. The update check is incremented by 1 every time a file is created, deleted etc. If you open a file in //over// mode and then close it again without doing anything, this number will increment, this is because you have (just) overwritten the file!
 ---- ----
 \\ \\
Line 60: 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 132: 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 515: 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.
Line 584: Line 592:
 The table below shows a list of all the group sizes (in sectors) and the maximum size of a qxl.win file with that group size. The table below shows a list of all the group sizes (in sectors) and the maximum size of a qxl.win file with that group size.
  
-//In order to reduce the length of the page, I've created the table with pairs of columns rather than one. This means that there are not 124 lines, only 32. LOL Read across then down.//+<code> 
 +Group Size | Disc size (Mb) 
 +-----------|--------------- 
 +|        |    128       | 
 +|    5        160       | 
 +|    6        192       | 
 +|    7        224       | 
 +|    8        256       | 
 +</code> 
 + 
  
-^   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| 
-|    8|   256| |    9|   288| |   10|   320| |   11|   352| 
-|   12|   384| |   13|   416| |   14|   448| |   15|   480| 
-|   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.1550783453.txt.gz
  • Last modified: 2019/02/21 21:10
  • by norman