det@hawkmoon.MN.ORG (Derek E. Terveer) (04/06/88)
I have in my custody an Sco Xenix 2.1.3 system (corum.UUCP) that seems to work just fine and dandy, but i'm curious about one thing (well alright, many things, but i don't want to drown you out there... (:-)); the diagnostic/ informational messages that are printed on the system console at boot time include one about the line frequency: "HZ=50". Now, we are in the US so we should be at 60Hz, right? Why is this set to 50? Does it affect the system much? Would the system be faster if its reset to 60? Should i ignore this message? I looked through all the include files i could find and these slices are all the references i could find to "HZ": */ #ifdef M_I86 #define HZ 20 /* Ticks/second of the clock */ #define SSIZE 1024 /* initial stack size (bytes) */ #endif #ifdef M_I286 #define HZ 50 /* Ticks/second of the clock */ #define SSIZE 4096 /* initial stack size (bytes) */ #endif */ #ifdef M_I86 #define HZ 20 /* Ticks/second of the clock */ #define SSIZE 1024 /* initial stack size (bytes) */ #endif #ifdef M_I286 #define HZ 50 /* Ticks/second of the clock */ #define SSIZE 4096 /* initial stack size (bytes) */ #endif Hopefully not being a bimbo with a stupid question, derek -- Derek Terveer det@hawkmoon.MN.ORG uunet!rosevax!elric!hawkmoon!det
ericg@sco.COM (Mwa ha ha) (04/08/88)
det@hawkmoon.MN.ORG (Derek E. Terveer) wrote in article <132@hawkmoon.MN.ORG>: >include one about the line frequency: "HZ=50". Now, we are in the US so we >should be at 60Hz, right? Why is this set to 50? Does it affect the system The interrupt timer frequency and the frequency of common alternating current in the US have as much in common as a liverwurst sandwich and a girraffe.. i.e. none. The HZ=50 is the rate in which the interrupt controller chip is sending interrupts. >much? Would the system be faster if its reset to 60? Should i ignore this >message? > If you set it to 60, strange things would occur, most notably your software clock will run fast. >I looked through all the include files i could find and these slices are all >the references i could find to "HZ": > > */ > #ifdef M_I86 > #define HZ 20 /* Ticks/second of the clock */ > #define SSIZE 1024 /* initial stack size (bytes) */ > #endif In other words, XT machines have interrupt timers that run at 20 Hz > > #ifdef M_I286 > #define HZ 50 /* Ticks/second of the clock */ > #define SSIZE 4096 /* initial stack size (bytes) */ > #endif > But AT machine's interrupt timers run at 50 Hz >Derek Terveer det@hawkmoon.MN.ORG uunet!rosevax!elric!hawkmoon!det -- I do not speak for SCO, I barely have enough room for my own opinions. "When there is no more room in the river, the trout shall walk the earth." Eric Griswold |<help! i'm caught in the middle of a .signature>| ericg@sco.com
davidsen@steinmetz.ge.com (William E. Davidsen Jr) (04/08/88)
The HZ value is the number of clock ticks per sec. It is not related to
the power line frequency in any way. On an 8086 machine it is set to
20 ticks/sec, while on a 286 it's 50.
--
bill davidsen (wedu@ge-crd.arpa)
{uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me