Posts Tagged ‘windows xp’
I have been reading Brian Madden‘s perspectives regarding Windows 7, the Virtual Desktop Infrastructure (VDI) and the uplift in adoption that VDI and desktop hypervisors will experience due to the draft created by Windows 7 migration.
I was asking myself, “Why is the Windows 7 migration such a big deal?” Windows 7 is after all an incremental release of Windows Vista. The fact of the matter is that customers did not migrate to Vista over the past two years and continue to run on XP even today. A significant majority of customers have shied away from migrating from XP to Vista on their existing computer hardware because of driver compatibility between XP and Vista – drivers written for XP may not work with Vista, they may have to be rewritten.
SeattlePI.com has posted Microsoft internal email unsealed by a federal judge that provides a historical insight into Windows Vista’s hardware and software compatibility problems. It reports that compatibility problems turned Mike Nash’s (Corporate VP, Windows Product Management) $2,100 PC into nothing more than an “email machine”. Steve Sinofsky, (Senior VP for Windows) admits to Microsoft’s lack of clarity and focus around setting and managing the expectations of hardware device vendors
We need to be clearer with industry and we need to decide what we will do and do that well and 100% and not just do a little of everything which leaves the IHV [Independent Hardware Vendors] in a confused state.
The primary causes for the incompatibilities are
- Vista supports a new audio/video driver model due to a massive change in the underpinnings for audio/video between XP and Vista.
- Vista enforces a new security model for device drivers
As a result, many XP drivers, across the board for printers, scanners, wan, accessories (fingerprint readers, smart cards, tv tuners), and so on, don’t run under Vista and their devices become unusable. There seems to be little incentive for device manufacturers to design, develop, test and support brand new drivers for “legacy” XP devices on Vista. Here are the 10 most common hardware problems that may be encountered by a Vista user.
The migration experience with Vista was so poor that Microsoft took the unprecedented step of providing a downgrade path to Windows XP.
Shrinking a VM today is a time consuming process: zero out the free blocks, defrag, use vmware’s tools to shrink it partition by parition. I wanted a tool which would tell me after doing all that how much would it help. This turned out to be a complicated process as you have to find the free clusters in NTFS and find out whether they are actually allocated as in sparse VMDK files all blocks may not be allocated. I ran the tool on some VMs see below: Windows 2003, Windows NT & a couple of XP VMs.
fcp -f c:\work\vhd\w2k3.vhd
NTFS Free Sectors 594632
Free Sectors Allocated in Virtual Image 294496
Maximum Possible Saving by Shrinking 143 MB
fcp -f “c:\work\vm\w1\Windows XP Professional.vmdk”
NTFS Free Sectors 1049160
Free Sectors Allocated in Virtual Image 883144
Maximum Possible Saving by Shrinking 431 MB
fcp -f “c:\work\vhd\Windows XP Hard Disk.vhd”
NTFS Free Sectors 30124176
Free Sectors Allocated in Virtual Image 847013
Maximum Possible Saving by Shrinking 413 MB
fcp -f “c:\work\vm\wnta\wnta.vmdk”
NTFS Free Sectors 27724512
Free Sectors Allocated in Virtual Image 71656
Maximum Possible Saving by Shrinking 34 MB
I am thinking of releasing the tool, it only supports vmdk and vhd files today with NTFS file system. If you would like to get an early release, would be thrilled to share let me know.
Experience with running out of storage
Background about sparse files, Windows NTFS and VHD
- NTFS Compression, sparse files and operations on them
- UNIX sparse files
- Be Careful with VHDs and Windows XP Compressed Folders
- Why do VHD’s grow?
- What is a VHD file, what is a disk image?
VHD Pre-Compactor & Compactor
When you create a new VM you can pre-allocate all the storage in one shot or let the storage grow on demand. In the latter case, the VM uses a sparse file
- Compact your Microsoft Virtual PC 2004 VHD Files
- Compressing Microsoft Virtual Server 2005 VHD files
- Virtualization with Microsoft Virtual Server 2005 by Roger Dittner, David Rule, Jr., Ken Majors
- How to compress Microsoft Virtual PC 2007 hard disks
- Compressing Microsoft Virtual PC 2007 Images
- Compressing Microsoft Windows Server 2008 Hyper-V disk images
VMDK Wipe & Shrink
3rd Party (Not from MSFT & VMW)
Rsync: for transferring files between machines
- IZO: Applications of Large-Window Compressions to Virtual Machine Management (Mark et al. IBM Almaden, USENIX, Nov 2008)
- CZIP [ppt][paper]
- redundancy elimination within large collections of files
- Data Domain SISL
- Hyperfactor (IBM Data Depulication)
- Network Applicance
I did some analysis of the layout of a VMDK file. The graph below shows this analysis: x-axis is the distance in the vmdk file for two logically adjacent blocks(sectors). For for example is block 33 is at offset 3467 and block 34 is at offset 3468 then the distance in the vmdk file is 3468-3467=1. The Y-axis is log to the base 2 of the frequency of the distance.
The graph shows that most logically adjacent blocks have adjacent offsets in the vmdk file. This file had a grain size of 128, so you would expect that only 2/128 sectors would have non-adjacent neighbours (1/64). That is roughly the case. The rest of the distances are clustered around multiples of 128 (as one would expect?). I am not sure if this has to do with NTFS allocating blocks in some sequence or VMW workstation expanding the disk in a particular way.
The vmdk was a windows vmdk 4GB disk with windows XP. Very little use after installing the base OS. Installed a couple of packages like Flex Builder.
Another interesting plot would be to plot the actual distance on the physical disk on the host. Thats next.
My envrionment is the same as the one stated in my earloer post:
- Outlook 2007 crashes intermittently (I usually shut it down gracefully before starting the VM)
- Wireless drops intermittently but reconnects quickly
- One USB port not recognized by host OS (XP)
- Windows XP SP3, Office 2007, IE 7, Firefox, Dell D630 Intel Duo Core with 2GB of RAM, 60 GB Hard drive
- VMWare Workstation 6.5 running Fedora 9 with X windows or Ubuntu 8.10 base OS, no other apps running
With just one VM running here is what happens to the host
- Accessing C:\ drive takes noticeably long – is there a file system filter driver in the IO path even when the VM is not running ? There seems to be a non-linear path name resolution / drive mapping logic.
I should figure out whether I can report this somewhere on the VMWare site. They’ll most likely ask for a VM snapshot of my laptop, recursive packaging of VM’s – wonder what new behaviors that will expose?