[fpc-pascal] File Enumeration speed

[SteveG]

I am enumerating thru large numbers of files on my disk, and find I cant 
come close with findfirst / findnext to matching the speed of cmd line 
apps available in linux :eg ls / du

I have a fairly tight file search function, and dont see how to gain 
more speed

Would anybody know what the limiting factors would be ?

does the operating system keep an index somewhere ?

Thanks - SteveG