Category: English

Pot, kettle, black

The key to being a religious zealot is to criticize (real or made-up) characteristics of other religions while ignoring the very same characteristics in your own:

The earliest writings that are known to exist about the Prophet Mohammad were recorded 120 years after his death. All of the Islamic writings (the Koran and the Hadith, the biographies, the traditions and histories) are confused, contradictory and inconsistent. Maybe Mohammad never existed. We have no conclusive account about what he said or did. Yet Moslems follow the destructive teachings of Islam without question.

You could say the exact same thing about Jesus of Nazareth and the gospels. Muhammad’s existence is corroborated by contemporary non-Muslim sources and is just as much a historical fact as that of Jesus of Nazareth.

Islamic Law is totalitarian in nature. There is no separation of church and state. It is irrational. It is supposedly immutable and cannot be changed. It must be accepted without criticism.

The separation of church and state is a modern concept that dates back to the late eighteenth century. As for totalitarianism, irrationality and immutability: Have you actually read Exodus and Leviticus?

A Muslim does not have the right to change his religion. Apostasy is punishable by death.

Christianity is not known for its kind treatment of apostates and heretics.

Off by one

I made a small modification to phybs to verify the function of jumpers 7-8 on the WD Advanced Format drives (see here and here). It is supposed to cause the disk to internally shift every write by one sector, so that a write to sector 63 (where the first partition on a PC normally starts) actually goes to sector 64, which coincides with the beginning of a physical 4,096-byte sector. These numbers confirm this:

   count    size  offset    step        msec     tps    kBps
   32768    4096       0   16384       78631      34    1666
   32768    4096     512   16384       79880      33    1640
   32768    4096    1024   16384       73164      36    1791
   32768    4096    1536   16384       77727      34    1686
   32768    4096    2048   16384       76975      35    1702
   32768    4096    2560   16384       74970      36    1748
   32768    4096    3072   16384       79379      34    1651
   32768    4096    3584   16384       28094      96    4665

The firmware on the disk shifts everything forward by 512 bytes, so all these passes are unaligned except the last one, because 3,584 + 512 = 4,096.

Disks and equipment

Here is a quick overview of the disks used in my tests:

Brand Model Capacity Speed Interface Notes
Western Digital WD4000AAKS 400 GB 7,200 rpm SATA 3 Gbps  
Western Digital WD10EARS 1 TB > 5,400 rpm SATA 3 Gbps 1
Western Digital WD20EARS 2 TB > 5,400 rpm SATA 3 Gbps 2
Western Digital WD20EADS 2 TB > 5,400 rpm SATA 3 Gbps 3
Hitachi HDS722020ALA330 2 TB 7,200 rpm SATA 3 Gbps 3

The computer runs FreeBSD 9 on an Intel E6600 with an ICH9 chipset and 4 GB RAM. For convenience, the disks were tested in an Akasa Duo Dock connected by eSATA cable to one of the ICH9 SATA ports.

1 Kindly provided by Alastair Hogge

2 Kindly provided by GetOnline Ltd.

3 Kindly provided by Dansk Scanning AS

Benchmarking Advanced Format drives

Important: due to a bug in my benchmark program, the tps numbers in this post are incorrect. See here for the correct numbers.

In the previous post, I discussed Western Digital’s “Advanced Format” drives and the problems caused by their misreporting their real, physical sector size.

I wrote a benchmark utility to demonstrate the performance penalty of unaligned accesses and uncover a drive’s physical sector size. What it does is write blocks of zeroes varying size at regular intervals. For each block size, it writes a total of 128 MB at intervals of four times the block size, and at an offset that varies from 512 bytes up to half of the block size. Continue reading “Benchmarking Advanced Format drives”