Lab notes updates to SL simulator deployments

Courtesy of Linden Lab

It has long been a tradition in Second Life that the main grid simulators and the regions they support are split between a number of channels:

  • The main channel, called Second Life Server, or SLS, which has the majority of simulators / regions running on it (roughly about 70%).
  • Three core release candidate (RC) channels, code-named BlueSteel, Magnum and LeTigre – each of which may account for roughly 10% of the simulators / regions.
  • Assorted smaller RC channels (such as Snack and Cake), that come and go according to needs – they may draw their simulators / regions from the SLS channel or the main RCs or a combination thereof.

This division is designed to allow a flexibility of approach to deploying updates, particularly those that may contain new features or have specialist updates such a new throttles or security changes, as these can be deployment to one or two of the RC channels first to test how they work under fully 2live” conditions (which the Lab, with the best will in the world cannot possibly fully test prior to deployment), and then removed with minimal grid disruption should anything untoward happen.

These RC deployments generally take place every Wednesday. If all goes well, and depending on how many different simulator updates are on the larger RCs, one will generally be “promoted” to the SLS channel the following Tuesday, having spent a week on one or more RCs. there are some variances in this, depending on what is going on (significant changes or new feature might be gradually deployed from one to two to all three RCs over a period of time, and then to the SLS channel, for example), but you should get the general idea from this, if you weren’t previously aware of how things work.

These (generally) weekly deployments are reflected in my Simulator User Group updates, where I list the deployments in terms of the SLS channel and the three core RC channels (the Lab doesn’t always acknowledge when a very small RC is being used).

However, on Monday, August 26th, Linden Lab announced upcoming changes to how simulator changes are going to be handled, and while the deployment methodology will remain the same (SLS channel deployments on Tuesdays, RC deployments on Wednesdays), there will be some differences, notably:

  • Starting with a deployment to one of the RC channels, the channel name will no longer be visible through the viewer (Help > About) nor will it be open to LEL query  – the channel name will simply be listed as “Second Life Server”, the same as the “main” channel. Over the next couple of weeks this will be true for all RC channels.
  • This means that when reporting simulator issues, just referencing the channel name will no longer be sufficient – users must use the simulator version number. This is displayed in Help > About, alongside the channel name:
Going forward from week =35, simulator issues should be reported using the simulator code version number, not the channel name (“SLS”, “BlueSteel”, etc.).

The reasons for making these changes are defined as being twofold:

  • To provide the Lab with better data on the performance and reliability of the server updates, and allow for better monitoring (presumably via the additional tools and internal changes the Lab has been making to the simulator code for the last few months).
  • To avoid spurious associations between the RC channels and capabilities. For example, the idea that one RC channel runs on better (or worse) hardware than another or the SLS channel; or that issues being experienced *must* be the result of an RC deployment, purely on the basis that that was either the last deployment made, or the user happened to be on an RC channel when they encountered an issue (regardless of whether the code may actually have caused the problem or not).

It is also noted in the official blog post that while simulator code version numbers will be the preferred means of reporting issues, channel names will continue to be recognised by Support for matters of testing:

Future improvements will make each RC channel a better model of the Grid as a whole. Support will continue to be able to accommodate Region owners’ requests that a Region be in the RC for a particular feature or fix they want as soon as possible, or that it be excluded from any RC.

It’s currently not clear if these changes will also impact the channel reporting capabilities in TPVs like Firestorm (which can pop-up the name of the simulator channel when moving from one to another) or not.

A final note in the official blog indicates that simulator release notes will be moving to the same system as is now used for viewer release notes. When this happens, I can only hope it is managed better than is currently the case for viewer release notes, where updates viewers may be references on the Release Notes page OR the Alternate Viewers page OR the Available Viewers Index on what seems to be the flip of a coin.

Please refer to the official blog post for full details of the changes.

An Autumn’s Cherishville in Second Life

Cherishville, August 2019 – click any image for full size

Shawn Shakespeare suggested we make a further return visit to Lam Erin’s Cherishville over the weekend, noting it had been redesigned in readiness for autumn’s arrival in the northern hemisphere. So we hopped on the Second Life express and alighted at St. Bronxton Railway Station, a quaint little end-of-the-line station that is one of Cherishville’s many new features to capture the eye and the lens.

The region is now centred on a channel that cuts it neatly in two from east to north-west. With the stone-built banks topped by paved footpaths and spanned by a single bridge, the channel is bordered on either side by an assortment of buildings; so much so, that despite facing open water at either end, it has the look and feel of being the mouth of a small but navigable river, and the buildings on either side are the result of a estuary township, the people drawn here for the open seas and the opportunities for fishing and coastal commerce.

Cherishville, August 2019

This little township is distinctly of two halves. The west bank of the river, which includes the landing point and the aforementioned railway station (set back from the river’s edge) has – to me at least – a very English feel to it. With the buildings crowding the waterfront, I was immediately put in mind of a small river estuary in Cornwall or Devon; the stone-built houses and shops speaking of a place that had in the past grown up as a result of commerce along the coast. In fact, such is the look to that side of the river, I wouldn’t have been surprised if during our visits, Aram Khachaturian’s Adagio from Spartacus welled up in the background as the Charlotte Rhodes hove into view, James Onedin at the helm (Yes, a (possibly obscure) British TV series reference thrown in as well!).

Across the stone bridge, the east side of the river has a more American look and feel to it: posters advertise Connecticut and New England lobster, Martha’s Vineyard gets a mention and the fuel prices are in USD. Even the wooden buildings have the look and feel of rural Americana.

Cherishville, August 2019

But no matter what influences have been drawn into the design, both sides of the river have one thing in common – something also common to both sides of the Atlantic in the autumn: rain. To say this is coming down in buckets would be an understatement; for those so inclined, brollies, coats and wellies are the order of the day for a visit! Although truth be told, the rain (mesh elements places along the line of the river) add considerable atmosphere to the setting. It pounds the footpaths and board walks, given both a sheen that reflects lights (if you have ALM enabled!), while puddles set golden, red, orange and yellow leaves drifting under the influence of a gentle, rainy breeze.

Beyond the river and town, the land undulates in low, wooded hills or spread in flower-rich ground before dropping away to the water once more. A lighthouse raises a finger into the sky to the north-east, adding to the feel of this side of the river being  more American in setting, whilst on the west side, the land is cut in part by the tracks curving out from Bronxton Railway Station, whilst also easing its way to a shingle ribbon of coast looking south and out towards two smaller islands, each topped  by  a cabin.

Cherishville, August 2019

These cabins appear to be open to the public – at the time of our visit, the larger was unfurnished as well. However, as there are no obvious means to reach either of them save by swimming / flying, we didn’t venture any closer than the beach to find out, as we didn’t want to invade any privacy should either be for private use.

Not that any visit really is necessary: there is more than enough to see and photograph around the river front town and immediately behind its rows of buildings without every need to cross the water to the smaller islands. There are also plenty of spots scattered around when sitting and passing the time can be enjoyed – particularly along that southern ribbon of beach.

Cherishville, August 2019

There are admittedly one or two rough elements in the design. Some of these are somewhat down to the nature of the mesh beast – it’s possible in places to find yourself walking in raindrop splashes hovering at waist level. Others may well be because Lam is still tweaking the design – on my return run for photographs, he was shuffling buildings, sorting out hovering trees and carrying out some general furnishing.  Certainly, none of the is enough to completely spoil the setting or the autumnal feeling it imbues whilst wandering and exploring.

All told, another classic design from Lam, very different from its summer iteration (read here for more), but well in keeping with the upcoming seasonal change in the northern hemisphere (climate change allowing!), and very much worth the time to visit – as always, and photos welcome at the region’s Flickr group.

Cherishville, August 2019

SLurl Details

2019 viewer release summaries week #34

Logos representative only and should not be seen as an endorsement / preference / recommendation

Updates for the week ending Sunday, August 25th

This summary is generally published every Monday, and is a list of SL viewer / client releases (official and TPV) made during the previous week. When reading it, please note:

  • It is based on my Current Viewer Releases Page, a list of all Second Life viewers and clients that are in popular use (and of which I am aware), and which are recognised as adhering to the TPV Policy. This page includes comprehensive links to download pages, blog notes, release notes, etc., as well as links to any / all reviews of specific viewers / clients made within this blog.
  • By its nature, this summary presented here will always be in arrears, please refer to the Current Viewer Release Page for more up-to-date information.
  • Note that for purposes of length, TPV test viewers, preview / beta viewers / nightly builds are generally not recorded in these summaries.

Official LL Viewers

  • Current Release version 6.2.4.529638, formerly the Love Me Render RC viewer dated August 5, promoted August 12th – No  Change.
  • Release channel cohorts:
  • Project viewers:
    • Project Muscadine (Animesh follow-on) project viewer, version 6.4.0.530100, August 19..

LL Viewer Resources

Third-party Viewers

V5/V6-style

V1-style

  • No updates.

Mobile / Other Clients

Additional TPV Resources

Related Links

Space Sunday: to explore Europa

An artist’s impression of Europa Clipper (previously the Europa Multiple Flyby Mission), due for launch in 2022 or 2023 (depending on the launch vehicle used) making a flyby of Europa. Credit: NASA

There are a number of places within our solar system where life may have come to pass – and indeed, may still exist – beyond the Earth. There’s Mars, Saturn’s massive moon Titan, and the so-called “icy world” moons, such as Neptune’s Triton, Saturn’s Enceladus, and Jupiter’s Europa, all of which may harbour sub-surface oceans between their icy crusts and solid interiors.

Of these moons, Enceladus has shown clear signs of activity relating to the existence of a sub-surface ocean: the ESA / NASA Cassini mission captured images of great plumes of water erupting from the moon’s south polar region, and the Cassini vehicle passed through this plumes towards the end of its mission to “taste” them, confirm they were predominantly water.

However, the icy world that has garnered the most interest in terms of detailed study remains Jupiter’s Europa. Currently, there are two missions being developed to probe Europa in greater detail than ever before: NASA’s Europa Clipper and ESA’s Jupiter Icy Moons Explorer (JUICE).

Europe’s subsurface ocean as it might exist – a place that might support life. Credit: NASA

Europa Clipper has had something of an up-and-down ride. Originally, scientists wanted to send a vehicle to study all of the icy moons around Jupiter – Europa, Callisto and mighty Ganymede. However, the US $16 billion price tag for the mission (including vehicle development, launch and operation) was too high. It was scaled back to a more modest US $4.3 billion mission, the Europa Orbiter, which would have included a lander. Then it was scaled back again to a US $2 billion mission.

In 2014, the mission eventually morphed into the Europa Multiple Flyby mission: rather than placing a vehicle directly in orbit around Europa, this would put the vehicle in orbit around Jupiter  from where it would be able to make multiple fly-bys of Europa. This then became Europa Clipper – which has still suffered from attempts to axe it, surviving only because it has very strong support within the US Congress.

This support has allowed the mission to both receive continued funding and proceed through various design and review activities. As a part of this, on Monday, August 19th, 2019, NASA announced  that it had formally confirmed the mission can proceed to what is called Phase C, a process that will see the mission through the final spacecraft design and then on to assembly and testing.

We are all excited about the decision that moves the Europa Clipper mission one key step closer to unlocking the mysteries of this ocean world.

– Thomas Zurbuchen, NASA associate administrator for science

While Enceladus was the first moon where we positively witnessed plumes of water ice erupting from the surface (2005), evidence that similar outgassing may be occurring at Europa has been gathered by the Hubble Space Telescope. This information, gathered in the form of images, and data gathered by the magnetometer instrument carried by NASA’s Galileo space vehicle that surveyed Jupiter and his moons in the 1990s, offer the clearest indication that there is an ocean of water, possibly containing more than twice the volume of all the Earth’s oceans and sea combined, sitting beneath the surface ice on Europa.

The solar-powered craft  – solar power being a lot cheaper than nuclear RTGs – will carry a total of nine primary science instruments, with eight confirmed as being:

  • The Europa Thermal Emission Imaging System  (E-Themis) will provide high spatial resolution, multi-spectral imaging of Europa in the mid and far infra-red bands to help detect active sites, such as potential vents erupting plumes of water into space.
  • The Mapping Imaging Spectrometer for Europa (MIS), an imaging near infra-red spectrometer that will probe the surface composition of Europa, identifying and mapping the distributions of organics (including amino acids and tholins), salts, acid hydrates, water ice phases, and other materials. Scientists hope to be able to relate the moon’s surface composition to the habitability of its ocean.
  • The Europa Imaging System (EIS), a visible-spectrum wide and narrow angle camera instrument that will map most of Europa at 50 m (160 ft) resolution, and will provide images of selected surface areas at up to 0.5 m resolution.
  • The Europa Ultraviolet Spectrograph (Europa-UVS) instrument will be able to detect small plumes of material ejected by Europa, and will provide valuable data about the composition and dynamics of the moon’s exosphere.
  • The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON), a dual-frequency ice penetrating radar instrument designed to characterise and sound Europa’s ice crust from the near-surface to the ocean, revealing the hidden structure of Europa’s ice shell and potential water pockets within.
  • The Plasma Instrument for Magnetic Sounding (PIMS) working in conjunction with a magnetometer, PIMS is key to determining Europa’s ice shell thickness, ocean depth, and salinity. PIMS will also probe the mechanisms responsible for weathering and releasing material from Europa’s surface into the atmosphere and ionosphere and understanding how Europa influences its local space environment and Jupiter’s magnetosphere.
  • The Mass Spectrometer for Planetary Exploration (MASPEX) will determine the composition of the surface and subsurface ocean by measuring Europa’s extremely tenuous atmosphere and any surface materials ejected into space.
  • The Surface Dust Mass Analyser (SUDA), a second mass spectrometer that will measure the composition of small solid particles ejected from Europa, providing the opportunity to directly sample the surface and potential plumes on low-altitude flybys. The instrument is capable of identifying traces of organic and inorganic compounds in the ice of ejecta.

The ninth instrument will be a magnetometer, although this has yet to be sourced – the dedicated instrument, called Interior Characterisation of Europa using Magnetometry (ICEMAG) was cancelled due to spiralling costs and development complications. It will be replaced by a more “off the shelf” system that will be less sensitive than ICEMAG, but the mission team are confident they can compensate for this be more frequent re-calibration operations during the mission.

A pair of composite images of the side of Europa facing away from Jupiter. The rust / brown colour is likely the result of sulphur ejected from Jupiter’s inner moon Io being deposited on Europa by Jupiter’s radiation belt. The lines appear to be cracks in the surface, created by gravitational flexing of the Moon, which causes newer ice to form, indicative of water being forced upwards. Additionally, the yellow staining appears to be sodium chloride – the same as found in our own oceans – deposited on Europa as a result of material being ejected through the cracks. Credit: NASA/JPL / University of Arizona

Early concepts for a Europa mission – as noted above – included a lander – and possibly even a drilling mechanism and an automated submarine that could potentially be dropped under the ice and explore the ocean under it. These ideas were dropped – perhaps wisely – until more is known about the structure and thickness of the surface ice and exactly what lies beneath it. However, Europa Clipper has some additional payload capacity – around 250 kg – and NASA has been seeking ideas on what might be flown; some of the suggestions have included by a payload of supporting CubeSats or a small-scale lander.

While the Europa Clipper mission won’t actually orbit Europa, the multiple fly-bys will enable it to achieve almost global coverage of the moon, allowing for the widest amount of data to be gathered. This will be transmitted back to Earth in the 7-day periods between each close fly-by.

Currently, the mission launch date has yet to be finalised, and this in part depends on the selected launch vehicle. The preferred launcher is NASA’s upcoming Space Launch System (SLS). If used, this would see the mission launched in 2023, with the booster powerful enough to put Europa Clipper on a 3-year direct flight to Jupiter. However, there is no guarantee that SLS will be available in the proposed time frame, so NASA is also looking to use a commercial vehicle such as the SpaceX Falcon Heavy or the ULA Delta IV Heavy. Either of these would allow the mission to launch in 2022, but as they are less powerful than SLS, they would require Europa Clipper use 3 gravity assist manoeuvres, two at Earth and one at Venus, in order to send it on its way, increasing the transit time to Jupiter to 6 years.

Continue reading “Space Sunday: to explore Europa”