hcount raw file size

For a compressed file, I noticed hcount and read0 return its uncompressed format. I could understand for read function but
how do I get raw size as seen by ls?

http://www.timestored.com/kdb-guides/kdb-io-file-read-write-functions

`:tmp/t set t1

(`:tmp/tz;17; 2; 6) set t1

/ for me return the same number

hcount `:tmp/t        

hcount `:tmp/tz

-21!`:tmp/t