Re: About partition scheme.
Re: About partition scheme.
- Subject: Re: About partition scheme.
- From: "Li Flost.Dexiong" <email@hidden>
- Date: Wed, 04 Jul 2012 20:17:16 +0800
Hi Phil,
Thanks for your response.
please see my comment below
在 2012-7-4，下午7:45， Phil Jordan 写道：
> On Wed, Jul 4, 2012 at 8:14 AM, Li Flost.Dexiong <email@hidden> wrote:
>> /dev/disk1
>> #: TYPE NAME SIZE IDENTIFIER
>> 0: *16.1 GB disk1
>> 1: new_testdisk 16.1 GB disk1s1
>>
>>
>> I'm wandering why there is a #0 on my disk, when and how does it create?
>
> "disk 0" is the whole disk that the partition scheme sits inside. Look
> at the IOMedia hierarchy in IORegistryExplorer and it'll make more
> sense.
>
>> Also, are there any reference about how the "disk1s1" string was generate and record on my system?
>
> The "1" is generated from the location you set on your newly created
> IOMedia object like so:
> newMedia->setLocation("1");
> This only happens if the IOMedia object isn't "whole". If it's whole,
> a new diskX node is generated.
[Flost]: I had once try to init my newMedia using true as the "isWhole" argument. but this will cause the system panic.
my init of this media call was(this will not panic. but the #0 was created.):
8 #define UUIDLEN 16
9 typedef struct mydisk{
10 UInt32 DISKTYPE;
11 UInt32 headerlength;
12 UInt32 checksum;
13 UInt32 version;
14 UInt64 vollength;
15 unsigned char uuid[UUIDLEN];
16 }__attribute__((packed)) mydisk_t;
552 IOMedia * My_Scheme::instantiateMediaObject(mydisk_t* partition)
553 {
554 IOMedia *media = getProvider();
555 UInt64 mediaBlockSize = media->getPreferredBlockSize();
556 IOMedia *newMedia;
557
558 newMedia = new IOMedia;
559 if (newMedia) {
560 UInt64 partionBase, partionSize;
561 partionBase = 0; //OSSwapLittleToHostInt64(partition->base) * mediaBlockSize;
562 partionSize = partition->vollength; //OSSwapLittleToHostInt64(partition->size) * mediaBlockSize;
563
564 if (newMedia->init(partionBase, partionSize, mediaBlockSize, media->getAttributes(),\
565 false, media->isWritable(), "new_testdisk")) {
566 newMedia->setName("new_testdisk");
567 char location[12];
568 uuid_string_t uuid;
569 uuid_unparse(partition->uuid, uuid);
570 snprintf(location, sizeof(location), "%d", devcnt);
571 newMedia->setProperty(kIOMediaPartitionIDKey, devcnt, 32);
572 newMedia->setLocation(location);
573 newMedia->setProperty(kIOMediaUUIDKey, uuid);
574 } else {
575 newMedia->release();
576 newMedia = NULL;
577 }
578 }
579 return newMedia;
580 }
on line 565, if i set the false to true, the system got panic when my disk was insert into the system.
the mydisk_t was write the the disk before hand. and read in probe() function. and make the bit-order swap when read.
this InstantiateMediaObject was call by start function.
Is there any property that i could set this media is a whole?
or some way to prevent the #0 to be created?
>
> HTH
> phil
Best regards,
Flost.D.Li
email@hidden
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