[Coco] Super IDE vs. Drive Pak

[John Kent]

Actually this article says that 4K sectors are called Advanced Format 
and were implemented on 500GB drives.

http://techreport.com/discussions.x/18115
//http://en.wikipedia.org/wiki/Advanced_Format

I installed some WD10EA/R/S 1TB drives in my windows XP machine and they 
work fine so there must have been some patches to use them.

Off topic ... sorry.

John.

On 17/11/2011 1:28 AM, John Kent wrote:
> For some reason I thought CF cards were limited to 2GB.
> I can't remember why I thought that.
> If you look at the IDE register interface you'll see you should be 
> able to address up to 137GB.
> For 160GB drives and beyond, I'm not sure what happens.
> There must be some additional registers or bits somewhere.
>
> A2 A1 A0 D15-D8   D7-D0
> 0  0  0  Odd Data Even Data
> 0  0  1           Error / Feature
> 0  1  0           Sector Count
> 0  1  1           Sector Number    LBA  7- 0 (                  256 * 
> 512 =         131,072)
> 1  0  0           Cylinder Low     LBA 15- 8 (            256 * 256 * 
> 512 =      33,554,432)
> 1  0  1           Cylinder High    LBA 23-16 (      256 * 256 * 256 * 
> 512 =   8,589,934,592)
> 1  1  0           Select Card/Head LBA 27-24 ( 16 * 256 * 256 * 256 * 
> 512 = 137,438,953,472) * 2 Drives
> 1  1  1           Command/Status
>
> C/D/H = 1, LBA, 1, Drive, Head (LBA 27-24)
>
> 137.5GB * 16 = 2.2TB but then you lose the LBA and Drive bits
> (from the Apacer Compact Flash AP-CFXXX22 specification sheet)
> It assumes 512 byte sectors. I believe 2TB hard disks and beyond use 
> 4096 byte sectors which are only readable by Windows 7 and beyond and 
> not windows XP so perhaps you can squeeze another factor of 8 out of 
> the IDE register set.
>
> John
>
> On 16/11/2011 11:34 PM, Mark Marlette wrote:
>> All,
>>
>> Good thread!
>>
>> Input has been gathered and we will be making some changes at Cloud-9 
>> on the SuperIDE product based upon this great feedback. More to 
>> follow on that.
>>
>> Just want to clear this misconception. The SuperIDE DOES NOT have a 
>> size limit other than the CF spec itself. If you want to plug a 64GB 
>> CF, do so. The limitations are placed upon it are by NitrOS-9 and or 
>> HDB-DOS. This is a 24bit LSN, which is a bit over 4GB, IIRC. So is it 
>> practical to have a 4, 8, 16, 32,64GB CF on the CoCo? No, but if you 
>> want to you can.
>>
>> I ship with a 256MB just because it is a sweet size. 84MB partition 
>> for HDB-DOS and a 127MB partition for NitrOS-9, with another small 
>> partition with the remainder available. The reason for this is that 
>> there as several utilities under OS-9 that ASSUME a cluster size of 
>> one! Run those on a non 1 cluster size and POOF-BAM goes the drives 
>> structure. IMHO, not worth it. B&B are the biggest offender. Who 
>> would have thought we would be here today doing what we are doing? 
>> All GREAT tools, thus my basis of my partition sizes.
>>
>> How many people have more than 127MB of data/programs on their 
>> NitrOS-9 drive? Sure there are some. For those who want to have a 4GB 
>> partition, then you can do that on what ever size CF GREATER than 
>> that you select. Fill the 4GB partition up?? Not likely.
>>
>> Options are good. :)
>>
>> Any case, thank you all for the support and the great feedback. You 
>> will like the results. :)
>>
>> Regards,
>>
>> Mark
>> Cloud-9
>> http://www.cloud9tech.com
>>
>>
>

-- 
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