// jkh loves dd, and tells us why (edited mildly for clarity)
<jkh> dd has a long history...
<jkh> and since I'm easily the oldest person on this channel right now, let me ruminate...
<jkh> (my children will tell you that I ruminate a lot)
<jkh> A long time ago there was the OS called OS/360
<jkh> and God saw that it was god awful
<jkh> and it was
<jkh> We have bash/ksh/tcsh, on OS/360 that had JCL
<jkh> and JCL was god awful too
<jkh> if you look at (Yes everyone please actually click this link) the section on JCL under complexity
<jkh> You will see the JCL equivalent to linux's copy command "cp"
<jkh> Here you will see the beginnings of the dd command
<jkh> the thing that completely blows my mind about this JCL crap is---back when I first use (and last used; I only used it one fucking god awful time!!!) OS/360---the line where it says "DISP=(NEW,CATLG,DELETE),"
<jkh> This is from a newer version of OS/360. The one I used didn't have this.
<jkh> Along with knowing *exactly* how many CYLinder's of output your FORTRAN program was going to create
<jkh> note the "SPACE=(CYL,(40,5),RLSE)," line. This is exactly how many block of output your program is allowed to write.
<jkh> The conversion from character strings to CYLinders is horrible enough... but!!!
<jkh> The OS/360 machine I used, you had to go visit the troll in the basement. You asked him for some CYlinders.
<jkh> He had this big book in front of him. He looked through it and started reading off numbers.
<jkh> You copied those fucking numbers very very carefully.
<jkh> They were the exact CYLinder location for the data you were going to write.
<jkh> You put them in the DISP line like "DISP=(1223,8830,34,92020,3949230,939403,3881,040328)"
<jkh> You get the idea.
<jkh> And IF you should fuck up and type in the wrong fucking god damn fucking CYLinder number?
<jkh> you would write over someone else's files.
<jkh> This was 1979.
<Southern_Gentleman> jkh, yes we know you are as old as Adam :)
<jkh> Southern_Gentleman: you know I had an affair with Eve...
<Southern_Gentleman> see i was a freshman in hs in 79
<jkh> Southern_Gentleman: you be as old as me then