<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><br><span></span></div><div><span>Actually, I'm a little confused.</span></div><div><span>We have an assortment of information.</span></div><div><br></div><div>As I recall, the numbers of CHS isn't real anymore. The HD</div><div>hides that, although one can pull some number. <br></div><div>There is the underlying confusion of which each of</div><div>CHS starts at 0 or 1. So when I see CHS which don't add up</div><div>in the old classic way, my eyes glaze over and goes</div><div>to the next paragraph.<br></div><div><br></div><div>The CHS number may have attained some different meaning <br></div><div>of status or sector setting for the human installer ?<br></div><div><br></div><div>I do recall generally install selections of 512 bytes or 4096 bytes</div><div>had replaced the CHS thingys after drives kept
getting irrevokably</div><div>bigger. (Is 4096b/sector still big enough with 3Tbyte drives ?)<br></div><div><br></div><div>However, what can be counted on to be a boundary ?</div><div>Is it cylinders, or, it seems implication is on integer sectors.</div><div>So certainly bytes can be calculated, but modulo sectors ?</div><div>I saw another unfamiliar term in the thread, was it "cycles" ?<br></div><div><br></div><div>I'd really like to ignore anything that says "CHS".</div><div><br></div><div><br></div><div>Walt......</div><div><br><span></span></div><div>=====================================<br>For backward compatibility, max sectors is 63, heads is 255, in CHS. So 32/128 <br>would be 4MiB, not 8MiB, cylinders (and MiB, not GiB). The maximum 63/255 is <br>just under 8MiB, not a perfect boundary. Many people are using 32/64 for 1MiB, <br>although beware of translations that show up.<br><br>PC BIOS 16-bit Extended Int13h define
most of the legacy structures. For the <br>most part, I just note that things are stored in the first 1MiB (first 2048x512b <br>or 256x4KiB sectors) which is considered the MBR. This has been respected for <br>several years now by NT5.1 (XP/2003) and NT6.x (Vista, 7, 2008), so I usually <br>just stick with it.<br><br>None of this matters with 64-bit uEFI and GPT, of course.<br><br>-- Bryan<br><br>FYI, Virtually all fixed disks models today are coming with 4KiB sector size. <br>Many come with a jumper for 512b emulation that is on by default, but they are <br>4KiB. Until I see universal tool support for 4KiB, I leave the jumper on. <br>After all, most everything else is aligned on 4KiB or 8KiB structures anyway, <br>and shouldn't be accessing individual 512b bytes.<br></div><div> </div><div>Celebrating over 13,000 emails in my Yahoo Inbox !<br></div></div></body></html>