6.2.1 CourseCacheThe Course Cache thread is used to asynchronously retrieve items from the legacy Course Catalog System.
6.2.2 OfferingCache
The OfferingCashe thread is used to asynchronously retrieve items from the legacy Course Catalog System.
6.2.3 Course A class offered by the university.
Analysis Mechanisms:
- Persistency
- Legacy Interface
6.2.4 CourseOffering
A specific offering for a course, including days of the week and times.
Analysis Mechanisms:
- Persistency
- Legacy Interface
6.3 Process Model to Design Model DependenciesDiagram Name: Process Model to Design Model Dependencies
6.4 Processes to the ImplementationDiagram Name: Processes to the Implementation
6.4.1 Remote
* The Remote interface serves to identify all remote objects. Any object that is a remote object must directly or indirectly implement this interface. Only those methods specified in a remote interface are available remotely.
* Implementation classes can implement any number of remote interfaces and can extend other remote implementation classes.
6.4.2 Runnable
* The Runnable interface should be implemented by any class whose instances are intended to be executed by a thread. The class must define a method of no arguments called run.
* This interface is designed to provide a common protocol for objects that wish to execute code while they are active. For example, Runnable is implemented by class Thread.
* Being active simply means that a thread has been started and has not yet been stopped.
6.4.3 Thread
* A thread is a thread of execution in a program. The Java Virtual Machine allows an application to have multiple threads of execution running concurrently.
* Every thread has a priority. Threads with higher priority are executed in preference to threads with lower priority. Each thread may or may not also be marked as a daemon. When code running in some thread creates a new Thread object, the new thread has its priority initially set equal to the priority of the creating thread, and is a daemon thread if and only if the creating thread is a daemon.
7. Deployment View
A description of the deployment view of the architecture Describes the various physical nodes for the most typical platform configurations. Also describes the allocation of tasks (from the Process View) to the physical nodes.
This section is organized by physical network configuration; each such configuration is illustrated by a deployment diagram, followed by a mapping of processes to each processor.
Diagram Name: Deployment View
7.1 External Desktop PCStudents register for courses using external desktop PCs which are connected to the College Server via internet dial up.
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7.2 Desktop PCStudents register for courses via local Desktop PCs that are connected directly to the College Server via LAN. These local PCs are also used by professors to select course and submit student grades. The Registrar uses these local PCs to maintain student and professor information.
7.3 Registration ServerThe Registration Server is the main campus UNIX Server. All faculty and students have access to the Server through the campus LAN.
7.4 Course CatalogThe Course Catalog System is a legacy system that contains the complete course catalog. Access to it is available via the College Server and LAN.
7.5 Billing SystemThe Billing System (also called the Finance System) is a legacy system that generates the student bills each semester.
8. Size and PerformanceThe chosen software architecture supports the key sizing and timing requirements, as stipulated in the Supplementary Specification [15]:
- The system shall support up to 2000 simultaneous users against the central database at any given time, and up to 500 simultaneous users against the local servers at any one time.
- The system shall provide access to the legacy course catalog database with no more than a 10 second latency.
- The system must be able to complete 80% of all transactions within 2 minutes.
- The client portion shall require less than 20 MB disk space and 32 MB RAM.
The selected architecture supports the sizing and timing requirements through the implementation of a client-server architecture. The client portion is implemented on local campus PCs or remote dial up PCs. The components have been designed to ensure that minimal disk and memory requirements are needed on the PC client portion.
9. QualityThe software architecture supports the quality requirements, as stipulated in the Supplementary Specification [15]:
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- The desktop user-interface shall be Windows 95/98 compliant.
- The user interface of the C-Registration System shall be designed for ease-of-use and shall be appropriate for a computer-literate user community with no additional training on the System.
- Each feature of the C-Registration System shall have built-in online help for the user. Online Help shall include step by step instructions on using the System. Online Help shall include definitions for terms and acronymns.
- The C-Registration System shall be available 24 hours a day, 7 days a week. There shall be no more than 4% down time.
- Mean Time Between Failures shall exceed 300 hours.
- Upgrades to the PC client portion of C-Registration shall be downloadable from the UNIX Server over the internet. This feature enables students to have easy access to system upgrades.
Flightcase or road case? The term 'road case' is the more commonly used term in the United States, while 'flightcase' is the industry accepted word in Europe. I'm a European citizen, so I'll be using the term 'flightcase'.
It seems a lot of people like to build their own flightcases. Quite understandable, because a good ready-made case is expensive and building one yourself will cut the cost in half, roughly. You also get to choose your own dimensions and add extras. When you search the web for a flightcase how-to, you are left mostly empty handed. There are not a lot of DIY guides. My flightcases page used to take a lot of hits, and I got quite a few questions about the subject, so I decided to write this guide. I'll show you what tools and materials you need, what to look for, the inside scoop, how stuff works, and all that stuff, and I'll even provide two example cases.
So how do you go about this? The first thing you should do is locate a shop that carries aluminium flightcase extrusions and steel parts. Penn-Elcom is a large manufacturer of flightcase parts. I am very lucky to have an excellent supplier about 15 miles from home (Electra Breda). If it weren't for them I would've never started building cases. In 2013, Penn-Elcom established a website, Penn-Elcom Direct, which sells parts directly to large and small customers, catering to the whole of Europe. It's based in Germany, but offers a multi language (English, German, French, Spanish, Dutch) ordering process.
If you're not in Europe, you could look for one of Penn-Elcom's distributors. Penn-Elcom is a large, world-wide manufacturer, so they're probably everywhere. In any case (pun intended), they have a nice overview of what kinds of parts are available. Note however, that a lot of parts on Penn-Elcom.com are special order, and will probably not be available in retail. Whatever you do, don't try to be too cheap. A well-constructed flightcase built entirely out of standard flightcase parts is almost indestructable, because the parts form a proven, interlocked, system. Leave out one system component and the case becomes much less sturdy. By far, the most important part in a flightcase are the location extrusions, sometimes called closing extrusions.
Please note: I'm not a professional in this matter. I won't build you a case. I've built about a dozen cases and cabinets for personal use and have applied the knowledge gained from more experienced people into those cases.
Tools
Click thumbnails to zoom in. Click again to zoom out, or use cursor keys to walk through all images.
Saw
Obviously, you're going to need an electric drill and a hack saw or jigsaw (pictured is my personal work horse). To make precise 45° angle cuts, a miter jig is pretty much a necessity. If you want to cut your own panels (which I advise against when you're a beginner), a circular saw or table saw is preferred, but I get by with a jigsaw. You could of course do all wood cutting by hand. At the very least you'll get a decent workout!
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Pop rivets
And you need at least one special tool: a pop rivet wrench. These can be had for about US$20/€20. You'll also need special wood-type pop rivets, the 'groovy' ones. These can be hard to find, but the aforementioned shops should have them. Do not use plain pop rivets if there's nothing but wood for them to catch onto! They will not last! Been there, done that (fortunately, when a handle comes loose, the equipment is still protected by the case). I use 4 x 12 mm grooved pop rivets, as pictured. You press the to-be-fixed part firmly into position, and using the part as a template, drill all the way through the wood, then pop it, and continue to the next fixing hole. Alternatively, you could use screws. A bit more work and hassle, but definitely a possibility.
Drill bit
And I'd like to mention this separately: I use a very high grade 4.2 mm Cobalt steel (M42) drill bit. A razor sharp, long-lasting bit (I've been using the same bit for years) will save you a lot of frustration. Believe me. Not only will you be working faster, you'll also experience less 'runaway', because the bit will start cutting the moment your drill starts to turn. The bit you see in the picture is my actual one; it's drilled thousands of holes.
Parts
Panels
9.5 mm (3/8') plywood, plain or prelaminated. Prelaminated is expensive, but easy and incredibly durable. Plain plywood can be painted, preferably with a poly-urethane based coating. MDF is not suited for flightcases. Plywood is lighter, more durable, and more resistant to dings & dents, scratches and moisture.
Location
Closing extrusions, also known as location, locking or mating extrusions. These go in between case and lid(s) to make the closed case solid as a rock. They come in male/female, or reversible, and some types have gasket grooves for water tightness. These also come in lid maker style, where they're combined with an edge liner to build shallow lids with a single plywood panel. I haven't seen these in retail, though.
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Edges
'L' or 'single angle' extrusions. I prefer the 30 mm size. Used as edge liners. For heavy duty cases these also come in double angle style, where an extra fortification runs along the inside of the case. With these kind of edges, you don't build a wooden box first, instead you just pop rivet the panels into place.
Latches
Butterfly latches or drawbolts to keep the case closed. The recessed latches look professional, but ask yourself if you really need recessed ones. They are much harder to install, and break the location extrusion, making the case slightly less rigid. Surface mount latches are much easier to install.
Corners
Ball corners. Either stackable or not. Make sure they fit, if you plan to have a shallow lid. Most suppliers have 2-pronged ones for this, or even special ones for lids, with integrated L-brackets.
Hinges
Hinges, if you need them. Most suppliers carry removable ones and ones with a stop. The removable ones are usually not very sturdy, so if you must have a removable lid, use one hinge every 4-6 inches. I recommend at least 4 hinges on a 19' wide case. You could also fit extra latches on the hinged side, just to be sure.
Handles
Handles. I prefer recessed sprung handles. They're sturdy and don't take up much space, allowing you to build stackable cases even with handles on top and bottom. For a flat case, get a strap handle or a suitcase-style handle.
Brackets
L-brackets (a.k.a. cabinet braces). Use them to 'make ends meet', to cover up burrs and exposed sharp edges of the closing extrusions.
Dishes
Dishes, to install cable sockets or switches.
Casters
Casters, if you need them. Consider the braked swiveling type. Consider ball bearing wheels for heavy and rough use. Thank me later. Budget tip: Check IKEA.
19' Rails
For 19' racks, I prefer the sliding rail system. These allow you to slide in any number of caged nuts, allowing for a flexible vertical positioning of the equipment. I find it very useful to leave small vents in between an amplifier and a processor type device. The inside case width I use for these rails (mind the closing extrusions if you want the rails to sit flush with the case edges) is 19.25 inch, but this may vary across manufacturers. My point is: don't make the inside of your case exactly 19' wide.
Step by step:
Construct a closed box out of plywood. Use poly-urethane or normal white glue and thin 20 - 25 mm (3/4 - 1') nails, or tacks. The nails are only needed to hold everything together while the glue sets. You absolutely need to build it as a closed box first, so the closing extrusions will fit perfectly. Do this now, and thank me later. There's no way you can put together a perfectly matching box and lid. If the edges don't line up perfectly, the case will never close perfectly. Been there, done that. Please note that closing extrusions take up some space; about 6 mm (1/4'). This will make the case slightly deeper than the box you made.
Cut off the lid(s). Do this before you paint, or you'll scratch the paint while it's still getting up to full strength. For the reason stated above (to make sure the case closes perfectly), mark every part's orientation!
If you're not using laminated wood, paint the parts with some tough and scratch proof stuff. I use black poly-urethane paint for outdoor purposes. Don't put too much effort into the edges, they'll be covered anyway. For best results: sand, use a primer, sand lightly, put on a coat of paint, and depending on the opaqueness, sand very lightly and put on a second coat. Between each layer, stick to the directions on the can regarding its 'dry to recoat' time.
If you have dish-type recessed butterfly latches, hinges and/or handles, cut out their outlines. Again, you'll have to account for the added depth taken up by the closing extrusions! I always use some scrap pieces as guides. Alternatively, you can first fit the closing extrusions and then fit the recessed latches. I've done this several times. But in the end I find it easier to precut the dish outlines rather than first making the location extrusion fit perfectly, only to cut it anyway later on, if you get my drift. In most cases, I pick surface mount latches, because they are much easier to install.
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Fit the closing extrusions, cutting them in 45° angles, preferrably with a miter saw. I built a custom miter jig especially for this: a piece of 9 mm plywood mounted upright into a standard miter jig. It's worth the trouble for the (at least) 16 cuts you need to make for a case with a removable top and bottom.
Line the edges with L-extrusions using 2 pop rivets every 6-8 inches or so. You don't have to run them full length and miter them; just make sure they run underneith the corners you'll be putting on later.
Cover the transitions from closing extrusion to edge lining with L-braces to minimise the risk of skin cuts from the miter-sawn edges. You will probably have to round off the edges underneith the braces a bit. Because this step fixes the closing extrusions, keep the case firmly closed while you do this, using a couple of table clamps, a ratchet strap or weights. The braces can also be used to connect L-extrusions together on larger cases. That way you don't have to throw away pieces that aren't long enough.
Cover the corners with (duh) ball corners. Some of these require filing down the woodwork a bit. Please note that anything you put on the woodwork for protection adds quite a bit to the external dimensions, especially the larger ball corners.
Pop on the hinges, latches, and/or handles. I usually don't use rivets along the closing extrusions, but for very large cases this might be needed.
Install casters if you need them. Don't use screws or rivets for this; bolt them through and through with washers and nuts or T-nuts, and use something like Loctite or self locking nuts to prevent them from loosening. If your case is likely to tip over, use a separate base panel to separate the casters wider apart, for improved balance. Casters can be made removable if you install them on quick-release plates. Wheeled cases can be made stackable by installing caster dishes on top.
In a nut shell, that's about it. The main trouble will probably be getting those extrusions and parts. The rest shouldn't be a problem and requires minimal skills with wood and tools. Prior experience will be extremely helpful, though.
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This photo gear flightcase project also has its own separate page. But wait! There's more: a second photo flightcase.
As an example, and since I need one, I will be building a photo equipment suitcase. I figured it would be fun to use a standard hardware store 61 cm wide sheet and use it as efficiently as possible. So the case is going to be 61 cm wide. For my largest lenses to fit and still have some shock buffer, the case needs to be 12 cm high on the inside. Coincidently, Penn-Elcom has lid ball corners for 7 cm lids, so if I use two of these across the height of the case, the case will be exactly 12 cm, plus I won't need separate L-brackets and everything would sit nice and flush. But there's a small catch: because the male/female extrusions are not symmetrical, the female side has to have a 5 mm shorter wood panel for the separation line to be exactly in the middle. The reversible extrusions have the same problem. So for everything to indeed line up, and with the female extrusion on the bottom, I need to cut the bottom lid 5 mm shorter than the top lid.
Unfortunately, cutting this out of a single standard 61 x 122 cm sheet gets me a case depth of only 35 cm, so I'm going to cheat a bit and use a piece of scrap ply for one of the sides, increasing the depth to a more useful 41 cm. The circumference of the case along the front, sides and back will be 2 x 61 + 2 x 43 cm = 208 cm. Edge lining will be needed for both bottom and lid, so I'll need 416 cm. With these, you can always use slightly shorter cuts, since the corners will already have covering, so 4 meters will suffice.
Panel dimensions:
- Top and bottom: 61 x 41 cm
- Front and back: 61 x 13 cm
- Left and right: 43 x 13 cm
Bill of materials:
- one piece of 61 x 122 cm x 9 mm plywood (and a scrap piece)
- 1 length of 2 m male and female location extrusion (and some scraps)
- 2 lengths of 2 m single angle extrusion
- 8 lid ball corners 70 mm inside length
- 2 strut hinges
- 2 draw bolt latches with locks
- 1 suitcase handle
Since this is going to be a suitcase, butterfly latches are really unnecessary. I'm going to use simple lockable draw latches for this case. To prevent inadvertent dislocation of the case and lid, I'll not be using lift off hinges, but strut hinges.
So with all the calculations ready, let's hit it off. I'm going to follow my own step-by-step plan. Since I'm not using dish latches, step 4 is omitted. And since I'm using ball corners with integrated braces, and casters aren't needed, steps 7 and 10 are also omitted.
1
Construct a closed box out of plywood. If you need a step by step plan on how to put six wood panels together, it might be a good idea to try a less complicated project first. As you can see, I used hardwood ply, and if you look closely, you can also see I used tacks to put the box together. I also marked the separation line with a pencil.
2
Cut off the lid. I marked the bottom and lid with arrows on the inside, so I'm absolutely sure as to how they fit best.
3
Paint the parts with scratch proof black poly-urethane paint. I used half a spray can of primer that I had lying around and applied two coats of black paint. As you can clearly see, I made no effort at all to paint the edges.
5
Fit the closing extrusions, cutting them in 45° angles. In the second image you can see how it actually works. The bottom will catch the lid, forcing it into position.
6
Line the edges with L-extrusions. For this case I used 20x30 mm extrusions. The corners look like a hack job, and ideally, you'd miter them, but this will all be covered by the metal corners.
Close-up. This is what the pop rivets look like on the inside. I drilled all the way through the plywood, but the rivets compress into the wood completely. A little sandpaper will remove the burrs and make it flush. Now you can use very thin foam sheets, like I do, without the rivets showing through.
8
Cover the corners with ball corners. Keep the case firmly closed while you do this, using a couple of table clamps, or a ratchet strap, because this step fixes the location extrusions. The corners you see here have integrated braces and as you can see, I was a millimeter off when separating the case and lid. Under normal circumstances, this would be no issue. You would use braces and separate corners, and a piece of L-extrusion in between.
9
Pop on the hinges, latches and handles. Pop the location extrusions too, if you feel the need (I usually don't). Leave the clamps or ratchet strap. I put some steel washers under the hinges at their outer fixing points to prevent skewing. The large draw latches I used here required longer 4 x 18 mm pop rivets.
Originally I bought a sprung handle, but it was too large and would just hit the floor. So I went through the scrap heap at work and found this great looking stainless steel handle bar. It's fixed with two M10 nuts, so I can still unbolt it and put some rubber tube over it for carrying comfort. The aluminium strip under the handle's rivets is for aesthetic reasons.
Result
The end result. Looking good!
Those were the basic steps for the exterior. Since I want my photographic equipment well protected, I'm going to make a semi fixed divider sytem.
Foam
The interior. The lid was lined with egg crate foam. Then I put 2 ridges along the width of the case, making two 10.5 cm deep lens storage compartments. Everything was lined with self-adhesive neoprene foam. These are leftover cuts from work. I found some plastic panels to use as smaller vertical dividers.
Now the dividers are in place and I've pretty much settled on a layout. The only thing missing is a place to put the really small stuff, but I'm using a plastic box for now.
For another flight case example take a look at Photo flightcase 2.
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