[Coco] CoCoSDC performance issue - can someone try this from OS-9?

[K. Pruitt]

----- Original Message ----- 
From: "Nick Marentes" <nickma2 at optusnet.com.au>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Sunday, February 01, 2015 12:29 AM
Subject: Re: [Coco] CoCoSDC performance issue - can someone try this from 
OS-9?


> On 1/02/2015 5:41 PM, Allen Huffman wrote:
>>> On Feb 1, 2015, at 1:34 AM, Nick Marentes <nickma2 at optusnet.com.au> 
>>> wrote:
>>>
>>> The SDC reads a FAT32 file system on the SD card. I wonder if this is 
>>> creating the problem with a loaded SD card?
>> That was what I originally wondered about — if the huge 128MB files were 
>> fragmented, causing extra seeking around. I expect the low-level FAT 
>> firmware isn’t as elegant and speedy as what runs on our desktops.
>>
>> When I copied all my files off, then reformatted and moved them back, I 
>> would expect zero fragmentation of my .DSK files. I have 1.9GB out of 8GB 
>> available, so that may not have anything to do with it.
>>
>> At this point, I do not think it is CoCoSDC. I think it was me not 
>> realizing my 128MB drive only had 1-2MB of free space, so RBF is probably 
>> having to climb through a bunch of stuff to find spots for even tiny 
>> files. Maybe they are only at the end, and it has to read in 64K of 
>> bitmap every time looking for the empty bits at the end of the disk.
>>
>> Nick: There is up to 64K set aside as a bitmap marking which sectors are 
>> free. Each bit represents a sector, 0=free/1=used. Thus, if I want to 
>> write a tiny file that takes 256 bytes, it opens the bit map and has to 
>> parse through it looking for bytes with 0s in it to use.
>>
>> — A
>>
>
> You realize that defrag does little speed-wise on any memory based drive?
>
> There is no head seek on these, they just access the next block instantly 
> just like normal memory.
>
> Nick
>
>

You're right, but he's trying to make a larger contiguous block of space on 
the drive using defrag.  That should work as expected.