Posted on 2012-08-07 08:00:00
Tags: Numbers, Hardware
L1 cache reference ............................. 0.5 ns Branch mispredict .............................. 5 ns L2 cache reference ............................. 7 ns Mutex lock/unlock ............................. 25 ns Main memory reference ........................ 100 ns Compress 1K bytes with Zippy ............... 3,000 ns (3 us) Send 2K bytes over 1 Gbps network ......... 20,000 ns (20 us) SSD random read .......................... 150,000 ns (150 us) Read 1 MB sequentially from memory ....... 250,000 ns (250 us) Round trip within same datacenter ........ 500,000 ns (500 us) Read 1 MB sequentially from SSD* ....... 1,000,000 ns (1 ms) Disk seek ............................. 10,000,000 ns (10 ms) Read 1 MB sequentially from disk ...... 20,000,000 ns (20 ms) Send packet AU -> Netherlands -> AU .. 320,000,000 ns (320 ms)
Posted on 2009-10-18 22:00:00
Tags: Numbers
While Microsoft is preparing Windows 8 to be 128 bit compatible, a lot of people went from "as if we ever need that much space!". 64 bit to address your Random Access Memory, that is indeed enough (for now), but as a Storage Offset number it is nearly there: The terabyte harddisks already need 41 bits offsets!
bits addressable space 1 1 byte 2 2 3 4 4 8 5 16 6 32 7 64 8 128 19 256 10 512 11 1024 kilobyte 12 2048 13 4096 14 8192 <- memory of my first computer (Philips P2000T, 1982) 15 16384 16 32768 17 65536 18 131072 19 262144 20 524288 21 1048576 megabyte <- memory of my first "own" computer (AT 286, 1992) 22 2097152 23 4194304 24 8388608 25 16777216 26 33554432 <- my first harddisk in 1992. 27 67108864 28 134217728 29 268435456 30 536870912 31 1073741824 gigabyte <- memory of my computer in 2001 (p6) 32 2147483648 33 4294967296 34 8589934592 35 17179869184 36 34359738368 37 68719476736 38 137438953472 39 274877906944 40 549755813888 41 1099511627776 terabyte <- Fits on one single harddisk in 2008 for AU$ 130 42 2199023255552 43 4398046511104 44 8796093022208 45 17592186044416 46 35184372088832 47 70368744177664 <- for US$ 7,867 (Backblaze, September 2009) 48 140737488355328 49 281474976710656 50 562949953421312 51 1125899906842624 petabyte 52 2251799813685248 53 4503599627370496 <- Internet Archive in March 2009 54 9007199254740992 55 18014398509481984 56 36028797018963968 57 72057594037927936 <- Addressable in a 64 bit offset 59 144115188075855872 58 288230376151711744 59 576460752303423488 60 1152921504606846976 exabyte 61 2305843009213693952 62 4611686018427387904 63 9223372036854775808
Posted on 2008-02-28 15:00:00, modified on 2008-02-28 15:15:00
Tags: VegaStream, SNMP, Numbers
VegaStream has some very nice ATAs and T38 devices (still), but after the upgrade to VEGA400_R082S017 (8.2.17) every two and a half day their system.sysUptime counter gets resetted:
> Host : sjh-vega400 > Output: Uptime is less than an hour! (328.61 seconds) > Date : 2008-02-28 14:21:08
According to Nagios, this happens every two and a half days:
The device doesn't reboot, the sysUpTime count just goes back to zero. Device itself says it's up for 9 days.
About 2 days, 11 hours, 37 minutes, 62 seconds.
214682 seconds...
0x3469a...
Update
Thanks to callum on irc.oz.org/#bugs : 2 ^ 31 / 10,000, or an
overflow of the signed counter of the number of 100 microseconds.
Posted on 2007-10-09 17:00:00
Tags: Happiness, Numbers
This device measures... 2RU by 19 inch by (grabs measure-tape) 40 centimeters.
Posted on 2007-10-07 17:00:00
Tags: Happiness, Numbers
The number 36: When talking about health it's a good number: 36 degrees Celcius is good. When talking about a pregnant woman it's a good number: 36 weeks is still a month to go!
And for both situations, everything above 40 is bad.
Posted on 2005-03-24 16:38:41, modified on 2006-01-09 16:29:23
Tags: Coding, Numbers
If you're coding, interesting numbers will show up sometimes!
49 days = 49 days * 24 hours per day * 60 minutes per hour * 60 seconds per minute * 1000 ms = 4,233,600,000, or 0xFC579C00, or close to 0xFFFFFFFF. In other words, some unsigned 64 bit millisecond counter just overflowed.
Same story here, except that is an signed 64 bit millisecond counter.
| Number | Significance |
|---|---|
| 86400 | Number of seconds per day |