Wednesday Jul 23, 2008

Fast Booting Solaris

A veteran Java ONE keynote presenter, Perrone Robotics has developed some real interesting technologies which take the concept of using autonomous (i.e. unmanned) vehicles to a whole new level.  One of their key ingredients is the MAX software platform which utilizes common commercially available components to enable Perrone to very quickly and cost-effectively retrofit nearly any vehicle in short order.


The MAX robotics platform runs on a (roughly 4" x 6") low-power PC board atop Solaris and Sun's Java Real-Time System (Java RTS).  This combination gives Perrone the ability to leverage the huge Java development community, and assures that their critical software components behave in a predictable and deterministic fashion.

During the Java ONE 2007 conference, I was speaking with Paul Perrone about the notion of creating a minimized version of Solaris over which his platform might run.  The helicopter pictured above, boots from a relatively small (4-8Gb)  IDE flash drive, where standard Solaris takes up a substantial chunk.  It leaves them precious little space to collect valuable information like telemetry or terrain data.  Paul asked to revist this idea for a future project.  That's where we left off.

Not that we've ignored them since, but it wasn't until a year later that small Solaris reared its head again.  In addition to saving space, their main interest in this environment was in seeing how much faster Solaris might boot up.  The ability to be fully functional from power-up in as short a time as possible is of critical importance.

So before investigating what advantages there might be, let's provide some background information:

Hardware

Two separate systems were used, and for argument's sake, represent two ends of the x86 compute spectrum. 


Embedded Profile
Modern Profile 
System iGologic i84810
Panasonic Toughbook CF-30 (Rev. F)
CPU 1GHz Celeron M
Core 2 Duo L7500 1.60GHz
RAM 512MB 1GB
Disk 4GB Flash IDE Drive
Solid State SATA Drive

Operating Systems

Minimal configurations were created for Solaris 10 08/07 (Update 4) and OpenSolaris Nevada build 93.  These configurations boot entirely into RAM and consume less than 100MB ramdisk space.  With a little more effort they can be may significantly smaller.  The original blog post describing the environment is here.   You can download the framework for these hardware/OS combinations here, and can get a feel for the build environment by taking a look at this README.

Definitions

Within the context of this discussion, here are the key terms along with their meanings.

Total Boot Time: This is the time it takes from power-up till a user is prompted to log in.  Typically for a full Solaris installation, the windowing system must first start up and present the user with a login screen.  In a minimal Solaris environment, there is no windowing system.  Instead, the total boot time is defined as the time it takes from power-up till a user is prompted with the console login: prompt.

POST Time: POST or Power On Self Test is the time taken by the system at pre-boot to handle things like diagnostics,  BIOS and device initialization.  For this discussion, we'll define POST time as the time it takes from power-up until the user is presented with a GRUB boot menu.  We call out this segment of the total time because in many cases we are at the mercy of the PC/BIOS manufacturer and can't overly influence how quickly or slowly this proceeds.

Solaris Boot Time: The time it takes from being presented with a GRUB boot menu till a Solaris user is prompted to log in.  Again, depending upon whether a windowing system is configured or not, this may represent the time it takes to be prompted with a login screen or console login: prompt respectively.  This represents the segment of time that we can influence.

We can conclude from these definitions that:

   Total Boot Time = POST Time + Solaris Boot Time

Results

Embedded Profile: iGoLogic i84810 system 

OS
Post Time
Solaris Boot Time
Total Boot Time
 Solaris 10 08/07
13 sec
26 sec
39 sec
 OpenSolaris Nevada Build 93
13 sec
18 sec
31 sec 

Modern Profile: Panasonic Toughbook CF-30

OS POST Time
Solaris Boot Time
 Total Boot Time
 Solaris 10 08/07
 6 sec
 18 sec
 24 sec
 OpenSolaris Nevada Build 93
 6 sec
 9 sec
 15 sec

Conclusions/Notes

1. These times were taken by hand with the stopwatch feature on my Timex.  If anything, the times might be slightly shorter than actually recorded as there is a human delay in reacting to seeing the necessary prompts.  I ran the tests several times, and the same numbers consistently appear.

2. The version of the OS appears to matter a lot, as OpenSolaris nvx_93 boots up nearly twice as fast as Solaris 10 U4 on the same hardware.

3. The type of I/O device subsystem seems to be a big factor too.  For example, by switching out the IDE Flash Drive with a 5400 RPM IDE hard disk, i84810 total boot time decreased by about 6 seconds for both Solaris 10 and OpenSolaris. 

4. The minimal Solaris environment is currently only available in 32-bit mode.

5. With relative ease, Solaris can be configured to boot in less that 10 seconds on modern x86 hardware.  My unofficial record stands at 9 seconds (or slightly less).   No doubt it could boot faster on more robust hardware (eliminating POST time).  Any takers?

Wednesday Feb 07, 2007

Framework to Help Create Small Footprint RAM Resident Solaris Configurations

As Sun continues to avail more of its intellectual property to the community, the advantages Sun employees have regarding access to internal resources almost disappear.  In fact now when attempting to post questions to internal Sun mail aliases, I am often times redirected to the community.  The ramifications of this change hit me square in the gut this summer.

Having stumbled upon an internal project investigating how Solaris might be minimized for embedded use, I thought an interesting offshoot of this effort might be to create a ZFS appliance.  This device would boot from flash entirely into RAM, and all state would be maintained by the ZFS volumes.  Turns out this may be a little more tricky than anticipated, and future ZFS enhancements to Solaris (ZFS boot) may make this idea moot.

Based on an OpenSolaris ZFS discussion I initiated, observers went off and wrote about this topic elsewhere, some predicting that Sun would be releasing embedded ZFS appliances.  Whoa, hold on there, not so fast.  We have no plans (at least that I know of) to do any such thing.  This was nothing more than a pet project of mine.  Serves me right for announcing that I was a Sun employee.

But there was some good that came out of this dialog.  In addition to learning the valuable lesson of being careful what you write, interest in the notion of using Solaris as an "embedded" OS was quite apparent.   As a consequence,  I thought it might make sense to publish the basic framework used to create a custom Solaris miniroot.  Included below is the introduction section of the README file: 

1.0 Introduction

With the advent of Solaris 10 Update 1 and its migration to the grub(5) bootloader, it becomes quite feasible and straightforward to consider creating small footprint "embedded" versions of Solaris which boot directly into RAM. This project is based upon work done by Shudong Zhou to create a minimized Solaris for embedded use.  The doc/ directory contains some of the original documentation and scripts used to build such an environment.

It is expected that entities may want to provide further functionality and customizations to this environment. In order to assist in this endeavor, the original work has been enhanced to utilize the Java-based ant(1) build tool. For a further description on how a miniroot image is created, see the section on "Understanding the ant(1) build process".

You can download the framework here

Miscellaneous notes:

  • This framework assumes availability of a standard Solaris distribution.  Although not confirmed, I suspect it may not be real hard to augment for OpenSolaris.
  • The current framework produces a RAM resident version of Solaris that is about 60MB in size.  Note: there is no windowing included.
  • These configs are system specific.  The reference implementation for the included framework is an iGoLogic i84810 motherboard.  Some key specs are:
    • 1 GHz Celeron Processor
    • 512 MB RAM on board
    • Compact Flash slot on bottom of motherboard
    • 146mm x 104mm
    • Runs Solaris 10 U3 out of the box
    • For more info contact iGoLogic an http://www.igologic.com
  • Once an image is created, you'll need to set up grub(5) on your media.  Here's a pointer to a URL explaining Grub on a stick.  A copy of this URL is also included in the framework under the doc/ directory.
  • Here's a picture of the motherboard with ruler included to give you a feel for its size. 


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Jim Connors

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