Using Bochs I have the entry values into os2ldr when booted with BootJFS. One important note is that any of the filetable structure len fields will depend on the module version. Also, the 0x8800 segment might vary with machine types in the real world. It is calculated:<\/p>\n
DX == 0x1480 (00010100 10000000)
DH boot mode flags == mini-FSD is present, micro-FSD is present
DL drive number for the boot disk == 0x80<\/p>\n
DS:SI is a pointer to the BOOT Media’s BPB 8800:000B (0x8800B)<\/p>\n
ES:DI pointer to a filetable structure 8800:124A (0x8924A), filetable structure has the following format:<\/p>\n
; module locations<\/p>\n
8924A ft_cfiles dw 3
8924C ft_ldrseg dw 0x1000
8924E ft_ldrlen dd 0x0000AE00
89252 ft_museg dw 0x8800
89254 ft_mulen dd 0x00005000
89258 ft_mfsseg dw 0x7C00
8925A ft_mfslen dd 0x0000EAE9
8925E ft_ripseg dw 0
89260 ft_riplen dd 0<\/p>\n
; microFSD vector table<\/p>\n
89264 ft_muOpen_OFF dw 0x1A9C
89266 ft_muOpen_SEG dw 0x8800
89268 ft_muRead_OFF dw 0x1BD4
8926A ft_muRead_SEG dw 0x8800
8926C ft_muClose_OFF dw 0x1DAE
8926E ft_muClose_SEG dw 0x8800
89270 ft_muTerminate_OFF dw 0x1DD4
89272 ft_muTerminate_SEG dw 0x8800<\/p>\n","protected":false},"excerpt":{"rendered":"
Using Bochs I have the entry values into os2ldr when booted with BootJFS. One important note is that any of the filetable structure len fields will depend on the module […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"_links_to":"","_links_to_target":""},"categories":[7,31],"tags":[],"class_list":["post-36","post","type-post","status-publish","format-standard","hentry","category-bootldr","category-programming"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":37,"url":"https:\/\/www.mgreene.org\/?p=37","url_meta":{"origin":36,"position":0},"title":"ah… BootJFS and the process","author":"Mike","date":"May 18, 2008","format":false,"excerpt":"I\u2019m going to plagiarize from www.osfree.org and modify the text to fit my adventures with BootJFS.At the end of POST procedure the ROM BIOS initializes devices and gives control to int 19h interrupt routine, which loads 1st sector of the 1st boot device (a floopy, HDD or another). If the\u2026","rel":"","context":"In "bootldr"","block_context":{"text":"bootldr","link":"https:\/\/www.mgreene.org\/?cat=7"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":27,"url":"https:\/\/www.mgreene.org\/?p=27","url_meta":{"origin":36,"position":1},"title":"DosHlp Routines","author":"Mike","date":"August 17, 2008","format":false,"excerpt":"In brief, which is all I can do, the os2ldr contains some hardware dependent routines call DosHlp routines. Thanks to Pasha for pointing out that the ddk contains doshlp.inc which lists most of these (baseinc).The os2ldr contains a table of offsets that is passed to the kernel. The following is\u2026","rel":"","context":"In "bootldr"","block_context":{"text":"bootldr","link":"https:\/\/www.mgreene.org\/?cat=7"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":32,"url":"https:\/\/www.mgreene.org\/?p=32","url_meta":{"origin":36,"position":2},"title":"My os2ldr project","author":"Mike","date":"June 29, 2008","format":false,"excerpt":"I have had sometime to play and committed the results to the SVN page:http:\/\/www.assembla.com\/wiki\/show\/os2ldr","rel":"","context":"In "bootldr"","block_context":{"text":"bootldr","link":"https:\/\/www.mgreene.org\/?cat=7"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":612,"url":"https:\/\/www.mgreene.org\/?p=612","url_meta":{"origin":36,"position":3},"title":"MSDOS Booting on a snow day","author":"Mike","date":"January 23, 2022","format":false,"excerpt":"Anyway, big snow day in southeastern Virginia, so to kill time I was looking around at source on the internet. I had played around with the MSDOS start sequence before, but never looked closely. The typical start, considering a start from hard drive, is MBR load to 0x7C00, relocate to\u2026","rel":"","context":"In "msdos"","block_context":{"text":"msdos","link":"https:\/\/www.mgreene.org\/?cat=118"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":40,"url":"https:\/\/www.mgreene.org\/?p=40","url_meta":{"origin":36,"position":4},"title":"Easy gcc build environment","author":"Mike","date":"March 22, 2008","format":false,"excerpt":"Open Office for eCS-OS\/2 2.4 Beta1 is available (news post) and I installed it on my old SMP PIII box. Seems to work well! I guess the big milestone was just getting it going in the previous version.Also, Pasha has his updated os2ldr on hobbes (here). No chance to try\u2026","rel":"","context":"In "OS\/2"","block_context":{"text":"OS\/2","link":"https:\/\/www.mgreene.org\/?cat=24"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":290,"url":"https:\/\/www.mgreene.org\/?p=290","url_meta":{"origin":36,"position":5},"title":"New toy – ASRock J3455-ITX","author":"Mike","date":"November 29, 2018","format":false,"excerpt":"Part because of a mistake and part for fun, I purchased an ASRock J3455-ITX.\u00a0 I tried to boot a couple different OSs without much luck, I could not get CoreOS to boot or even a Gentoo LiveCD. Granted, it is low power and slow, so it might have been my\u2026","rel":"","context":"In "Gentoo"","block_context":{"text":"Gentoo","link":"https:\/\/www.mgreene.org\/?cat=12"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/wordpress.greenenet.net\/wp-content\/uploads\/2018\/11\/j3455_memory.png?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/wordpress.greenenet.net\/wp-content\/uploads\/2018\/11\/j3455_memory.png?resize=350%2C200 1x, https:\/\/i0.wp.com\/wordpress.greenenet.net\/wp-content\/uploads\/2018\/11\/j3455_memory.png?resize=525%2C300 1.5x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.mgreene.org\/index.php?rest_route=\/wp\/v2\/posts\/36","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mgreene.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mgreene.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mgreene.org\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mgreene.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=36"}],"version-history":[{"count":0,"href":"https:\/\/www.mgreene.org\/index.php?rest_route=\/wp\/v2\/posts\/36\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.mgreene.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=36"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mgreene.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=36"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mgreene.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=36"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}