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Added DiskDump option to create mountable albeit unbootable disks: --forceBPB

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This commit is contained in:
Jeff Parsons 2017-06-26 00:10:47 -07:00 • committed by Jeff Parsons
commit 74617db812
3 changed files with 94 additions and 6 deletions
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8
modules/diskdump/lib/diskdump.js
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@ -343,6 +343,7 @@ function DiskDump(sDiskPath, asExclude, sFormat, fComments, sSize, sServerRoot,
this.sJSONWhitespace = (this.fJSONComments? " " : "");
this.fXDFSupport = (argv && argv['xdf']);
this.sLabel = (argv && argv['label']);
this.forceBPB = (argv && argv['forcebpb']);
/*
* The dump operation itself doesn't care about sManifestFile, but we DO need some indication
@ -2780,7 +2781,7 @@ DiskDump.prototype.convertToJSON = function()
}
}
}
else if (bByte0 == X86.OPCODE.JMPS && bByte1 >= 0x22) {
else if (bByte0 == X86.OPCODE.JMPS && bByte1 >= 0x22 || this.forceBPB) {
/*
* I'm going to stick my neck out here and slam a BPB into this disk image, since it doesn't appear
* to have one, which should make it more "mountable" on modern operating systems. PC-DOS 1.x (and
@ -2792,8 +2793,11 @@ DiskDump.prototype.convertToJSON = function()
* 0x003-0x00A. For example, the word at 0x006 contains the starting segment for where to load
* IBMBIO.COM and IBMDOS.COM. Those same early boot sectors are also missing the traditional 0xAA55
* signature at the end of the boot sector.
*
* However, if --forceBPB is specified, all those concerns go out the window: the goal is assumed to
* be a mountable disk, not a bootable disk. So the BPB copy starts at offset 0 instead of SECTOR_BYTES.
*/
for (i = DiskAPI.BPB.SECTOR_BYTES; i < DiskAPI.BPB.LARGE_SECS+4; i++) {
for (i = this.forceBPB? 0 : DiskAPI.BPB.SECTOR_BYTES; i < DiskAPI.BPB.LARGE_SECS+4; i++) {
this.bufDisk.writeUInt8(DiskDump.aDefaultBPBs[iBPB][i] || 0, offBootSector + i);
}
console.log("warning: BPB has been updated");