[Coco] Another Coco Virtual Disk Util

Walt Zydhek walt at wzydhek.com
Tue Oct 22 22:40:54 EDT 2013


Hmm. I was unaware of the $20 used as a default for hard drives. All I had
read was the $08. Just checked. Sure enough. I will modify my code to create
new VHDs with $20 instead of $08. Other disk images will remain the $08.

-Walt Zydhek

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of Bob Devries
Sent: Tuesday, October 22, 2013 7:05 PM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] Another Coco Virtual Disk Util

It is my understanding that FLOPPY drives have a PD.SAS of 8, and HARD
drives use 32 ($20). That is done to prevent excessive fragmentation. I know
I have always used 32 on my hard drives. And isn't a VHD file just another
form of hard drive?

Gene Heskett can give us chapter and verse on this. He's the resident
expert.

Regards, Bob Devries
Dalby, QLD, Australia

----- Original Message -----
From: "Walt Zydhek" <walt at wzydhek.com>
To: "'CoCoList for Color Computer Enthusiasts'" <coco at maltedmedia.com>
Sent: Wednesday, October 23, 2013 11:54 AM
Subject: Re: [Coco] Another Coco Virtual Disk Util


> Yup, it's because each of the directories on your original have a minimum 
> of
> 20 sectors allocated to them instead of the default 8. The PD.SAS value is
> probably $20 instead of $08 in the virtual machine that formatted that
> original vhd. Do a dmode of that drive to see what the SAS value is set 
> to.
>
> -Walt Zydhek
>
> -----Original Message-----
> From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] 
> On
> Behalf Of Wayne Campbell
> Sent: Tuesday, October 22, 2013 6:47 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: Re: [Coco] Another Coco Virtual Disk Util
>
> Yes it was. The one I made today was using that one as source and copying 
> to
> a new one made with the new version today. The resulting free space is the
> same whether I use the original (Archives) or the second  (Archive), so 
> that
> tells me the original is using more space than the new, but over
> 100,000 bytes? That's alot of wasted space.
>
> Format defaults to 32 sector allocation. I forgot to change it to 1 sector
> allocations, but EmuDisk doesn't give me an option to change it.
>
> Wayne
> On Oct 22, 2013 9:15 PM, "Walt Zydhek" <walt at wzydhek.com> wrote:
>
>> Question.. the 2 files you just sent me. The NEW version (RiBBS
>> Archive.vhd, not plural), was it created and copied to BEFORE I fixed
>> the sector allocation in directory creation? Because it looks like it.
>> I see directories with their initial segment having a single sector.
>> And comparing it to the source version, I can see where the freespace
>> went in the source. It is using a default segment allocation of $20
>> (when directories are created, it allocates 32 sectors automatically
>> instead of the norm of 8). Please check your SAS value for your drive
>> in DMODE and see if it says $08 or $20. Regardless, if the Destination
>> version was created and copied to AFTER my fix to directory sector
>> allocation, then there is another bug there somewhere, as it should be
>> creating initial segments for directories at the default PD.SAS value
>> of 8 sectors.
>>
>> -Walt Zydhek
>>
>> -----Original Message-----
>> From: coco-bounces at maltedmedia.com
>> [mailto:coco-bounces at maltedmedia.com]
>> On
>> Behalf Of Wayne Campbell
>> Sent: Tuesday, October 22, 2013 5:30 PM
>> To: CoCoList for Color Computer Enthusiasts
>> Subject: Re: [Coco] Another Coco Virtual Disk Util
>>
>> I used RiBBS Archive (the new copy) as source.
>> I created a vhd image 5760 tracks, 64 sectors/track. Free Space after
>> format:
>>
>> 94323456
>>
>> I drag'd the root directory from the source vhd to the destination vhd.
>> Source vhd free space: 89308928 (this was the new copy yesterday)
>> Destination vhd free space: 89299200 (after copying) The original
>> source vhd free space: 89196000
>>
>> All disks had the same amount of free space when formatted and before
>> copying any files. There may be a few deleted files in the original,
>> but I don't think it's over 100k worth when the average filesize for
>> files I create are <4K overall.
>>
>> Wayne
>>
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