Hello David, <https://lh6.googleusercontent.com/-mr3KPBcih_U/U52qait6ikI/AAAAAAAABgY/6O5cger-FFg/s1600/Screen+Shot+2014-06-15+at+7.01.14+AM.png>
I now have a working system with programs that will run after making the correct AU entries in the Directory. I also put together a document that is pasted below, that could be included/corrected/added to etc. and filed with some of your work in this area. <https://lh6.googleusercontent.com/-mr3KPBcih_U/U52qait6ikI/AAAAAAAABgY/6O5cger-FFg/s1600/Screen+Shot+2014-06-15+at+7.01.14+AM.png> I really appreciate your help as this has been a lot of fun. <https://lh6.googleusercontent.com/-mr3KPBcih_U/U52qait6ikI/AAAAAAAABgY/6O5cger-FFg/s1600/Screen+Shot+2014-06-15+at+7.01.14+AM.png> <https://lh6.googleusercontent.com/-mr3KPBcih_U/U52qait6ikI/AAAAAAAABgY/6O5cger-FFg/s1600/Screen+Shot+2014-06-15+at+7.01.14+AM.png> *Directory Layout for S100 CF disk - what to do with larger files* <https://lh6.googleusercontent.com/-mr3KPBcih_U/U52qait6ikI/AAAAAAAABgY/6O5cger-FFg/s1600/Screen+Shot+2014-06-15+at+7.01.14+AM.png> <https://lh6.googleusercontent.com/-mr3KPBcih_U/U52qait6ikI/AAAAAAAABgY/6O5cger-FFg/s1600/Screen+Shot+2014-06-15+at+7.01.14+AM.png> The chart above, taken from an article by David Fry, illustrates the structure of a CF disk compared to the Altair sim disk. With the CF card, we need double the entries for AU since 1 AU now equals 4 sectors and not 8found in the sim. I want to use this to illustrate what happens if you encounter a file size greater than can be designated by a single directory entry. Example Directory entry: *00 48 4D 41 4B 45 43 50 4D 53 55 42* 00 00 *00* *XX* . HMAKECPMSUB . . . . *08 00* 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Where: *First row* *00 User #* *48 4D 41 4B 45 43 50 4D 53 55 42 Filename 8 + 3* *00 00 Used by CP/M* *00 Extent *(‘Occurrence’ of directory entries for this file – usually 0, discussed below) *XX # records this file contains* *Second row:* So, with 16 bytes in the second row, 1 AU being 4 sectors (512 bytes/sector), we could define the allocation units for a file of size 8 AU x 4 sectors x 512/sector = 16kb *So if a file exceeded 16kb, then the directory would look like this, a second pair of lines in directory with very subtle difference:* *00 48 4D 41 4B 45 43 50 4D 53 55 42* 00 00 *00* *56* . HMAKECPMSUB . . . . 08 00 09 00 0A 00 0B 00 0C 00 0D 00 0E 00 0F 00 *00 48 4D 41 4B 45 43 50 4D 53 55 42* 00 00 *01* *02* . HMAKECPMSUB . . . . <- SECOND ENTRY to allow more AU entries. 10 00 11 00 00 00 00 00 00 00 00 00 00 00 00 00 Notice that the second entry is the same in the first EXCEPT the *Extent byte* which is now a ‘1’ and the Record byte which is now a 2. In other words, the file is a total of 10 AU, or 40 sectors. Please let me know if anyone sees any error in this as it is based on my experiments and the 'CP/M Bible', Thanks, Thomas On Sunday, June 15, 2014 3:18:30 AM UTC-4, David Fry wrote: > > Hi Thomas, > > It's a little difficult to tell from a screenshot, > you need to make sure that when you copy files across you are placing the > file data in the next available Allocation unit boundry and not the next > available sector. I did include a quick and dirty excel calculator in the > zip archive that should help with this. > Go back to the first file that you transferred and check it out thoughly > and then see if you can launch the first file you transferred. > If you get stuck, post an image of the disk image and I will take a quick > look. > > Dave (yoda) and i are currently investigating/standardising the disk > format that I implemented with the intention of getting it to work with > cpmtools, this will make life easier to build images and transfer files > from the pc into a bootable cf card image, so don't run too far ahead as > the likely changes will make the original disk format unreadable. But by > all means continue if your intention is to learn more about disk layout, > I'm still learning too :-) > > regards > > David Fry > On Saturday, June 14, 2014 11:19:47 PM UTC+1, Thomas Owen wrote: > >> >> David, >> I have a Directory on the system now, but try to execute anything brings >> you right back to the command Prompt. Did I miss something in copying the >> files? >> >> >> <https://lh4.googleusercontent.com/-7gnmfBE0fwM/U5zKVldNggI/AAAAAAAABf4/2BLUDiY7W9Y/s1600/directory.jpg> >> >> >> Regards, >> >> Thomas >> >> On Saturday, June 14, 2014 4:31:24 PM UTC-4, David Fry wrote: >>> >>> Hi Thomas, >>> >>> I myself would like to know the answer on this one, >>> someone with a working CP/M system should be able to look at the >>> directory table entries and give an answer. >>> >>> regards >>> >>> David Fry >>> On Saturday, June 14, 2014 9:05:59 PM UTC+1, Thomas Owen wrote: >>> >>>> >>>> All, >>>> >>>> Now that I have a system that will boot to the A> from my IDE CF using >>>> the 'no holes' method outlined by David Fry, I am starting to add other >>>> files to the CF. >>>> >>>> I am populating my IDE CF card with files and modifying the Directory >>>> Table as described by David in his article 'Z80 CP_M 3.0 build.doc'. ( >>>> http://s100computers.com/My%20System%20Pages/IDE%20Board/Z80%20CP_M%203.0%20build.pdf >>>> ) >>>> >>>> With the scheme whereby 1 Allocation Unit (AU) = 4 Sectors (2kb) I run >>>> out of space on several Directory entries and need to make sure I am doing >>>> this correctly. >>>> >>>> In the image below, see the entry for *INITDIR.COM >>>> <http://INITDIR.COM>.* >>>> >>>> The program starts at Sector 338 (AU=45) and I need the additional room >>>> for AU entries. So, is it proper to simply add another line to the >>>> directory and continue with the AU assignments as shown here? >>>> >>>> 00 49 4E 49 54 ...................................................... >>>> INITDIR.COM >>>> >>>> *45 00 46 00 47 00 48 00 49 00 4A 00 4B 00 4C 00 4D 00 4E 00 ...* >>>> >>>> >>>> >>>> <https://lh6.googleusercontent.com/-0pMCjgWzqk0/U5yqYN-Jw7I/AAAAAAAABfc/N87q70fmfyk/s1600/AU-DIRECTORY.jpg> >>>> Thanks for any suggestions - >>>> >>>> Thomas >>>> >>>> -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
